Dioxolane derivative, liquid crystal composition, liquid crystal element, and liquid crystal display device

ABSTRACT

A dioxolane derivative represented by formula (G1) is provided. The explanation of the substituents is given in the specification. The use of the dioxolane derivative enables the production of a liquid crystal composition and a liquid crystal display device including the liquid crystal composition.

BACKGROUND OF THE INVENTION

1. Field of the Invention

One embodiment of the present invention relates to a semiconductordevice, a display device, a driving method thereof, or a manufacturingmethod thereof. In particular, one embodiment of the present inventionrelates to a novel dioxolane derivative, a liquid crystal compositionthat includes the dioxolane derivative, a liquid crystal element and aliquid crystal display device that include the liquid crystalcomposition, and manufacturing methods thereof.

2. Description of the Related Art

In recent years, liquid crystal has been used for a variety of devices;in particular, a liquid crystal display device (liquid crystal display)having features of thinness and lightness has been used for displays ina wide range of fields.

For higher resolution of moving images and less motion blur, shorterresponse time of liquid crystal has been required, and developmentthereof has been advanced (for example, see Patent Document 1).

As a display mode of liquid crystal capable of quick response, a displaymode using a liquid crystal exhibiting a blue phase can be given. Themode using a liquid crystal exhibiting a blue phase achieves quickresponse, does not require an alignment film, and provides a wideviewing angle, and thus has been developed more actively for practicaluse (for example, see Patent Document 2).

REFERENCE Patent Document

-   [Patent Document 1] Japanese Published Patent Application No.    2008-303381-   [Patent Document 2] PCT International Publication No. 2005-090520

SUMMARY OF THE INVENTION

An object of one embodiment of the present invention is to provide anovel dioxolane derivative that can be used for various liquid crystaldisplay devices. Another object is to provide a liquid crystalcomposition using the dioxolane derivative. Another object is to providea liquid crystal element and a liquid crystal display device eachincluding the liquid crystal composition.

Note that the descriptions of these objects do not disturb the existenceof other objects. In one embodiment of the present invention, there isno need to achieve all the objects. Other objects will be apparent fromand can be derived from the description of the specification, thedrawings, the claims, and the like.

An embodiment of the invention disclosed herein is a novel dioxolanederivative represented by General Formula (G1). The dioxolane derivativecan function as a chiral material in a liquid crystal composition.

In General Formula (G1), Ar¹ and Ar² independently represent hydrogen, asubstituted or unsubstituted aryl group having 6 to 12 carbon atoms, asubstituted or unsubstituted cycloalkyl group having 3 to 12 carbonatoms, or a substituted or unsubstituted cycloalkenyl group having 4 to12 carbon atoms; Ar³ and Ar⁴ independently represent a substituted orunsubstituted arylene group having 6 to 12 carbon atoms, a substitutedor unsubstituted cycloalkylene group having 3 to 12 carbon atoms, or asubstituted or unsubstituted cycloalkenylene group having 4 to 12 carbonatoms; m represents any of 1 to 3, and n represents any of 0 to 3; a¹and a² independently represent a substituted or unsubstituted alkylenegroup having 1 to 4 carbon atoms or a single bond; R¹ and R²independently represent hydrogen, a substituted or unsubstituted alkylgroup having 1 to 6 carbon atoms, a substituted or unsubstituted alkoxygroup having 1 to 6 carbon atoms, or a substituted or unsubstituted arylgroup having 6 to 12 carbon atoms; and R³ represents hydrogen, asubstituted or unsubstituted alkyl group having 1 to 6 carbon atoms, ora substituted or unsubstituted alkoxy group having 1 to 6 carbon atoms.

In General Formulae (G1), examples of the substituents on the aryl grouphaving 6 to 12 carbon atoms, the cycloalkyl group having 3 to 12 carbonatoms, the cycloalkenyl group having 4 to 12 carbon atoms, the arylenegroup having 6 to 12 carbon atoms, the cycloalkylene group having 3 to12 carbon atoms, the cycloalkenylene group having 4 to 12 carbon atoms,the alkylene group having 1 to 4 carbon atoms, the alkyl group having 1to 6 carbon atoms, and the alkoxy group having 1 to 6 carbon atoms arefluorine (F), chlorine (Cl), bromine (Br), iodine (I), a cyano group(CN), a trifluoromethylsulfonyl group (SO₂CF₃), a trifluoromethyl group(CF₃), a nitro group (NO₂), an isothiocyanate group (NCS), and apentafluorosulfanyl group (SF₅).

Another embodiment of the present invention is a dioxolane derivativerepresented by the following Structural Formula (100).

Another embodiment of the present invention is a dioxolane derivativerepresented by the following Structural Formula (101).

Another embodiment of the present invention is a dioxolane derivativerepresented by the following Structural Formula (102).

Another embodiment of the invention disclosed herein is a noveldioxolane derivative represented by General Formula (G2).

In General Formula (G2), Ar¹ and Ar² independently represent hydrogen, asubstituted or unsubstituted aryl group having 6 to 12 carbon atoms, asubstituted or unsubstituted cycloalkyl group having 3 to 12 carbonatoms, or a substituted or unsubstituted cycloalkenyl group having 4 to12 carbon atoms; Ar²³ and Ar²⁴ independently represent a substituted orunsubstituted pyrenyl group or a substituted or unsubstituted naphthylgroup; a¹ and a² independently represent a substituted or unsubstitutedalkylene group having 1 to 4 carbon atoms or a single bond; and R¹ andR² independently represent hydrogen, a substituted or unsubstitutedalkyl group having 1 to 6 carbon atoms, a substituted or unsubstitutedalkoxy group having 1 to 6 carbon atoms, or a substituted orunsubstituted aryl group having 6 to 12 carbon atoms.

In General Formula (G2), examples of the substituents on the aryl grouphaving 6 to 12 carbon atoms, the cycloalkyl group having 3 to 12 carbonatoms, the cycloalkenyl group having 4 to 12 carbon atoms, the pyrenylgroup, the naphthyl group, the alkylene group having 1 to 4 carbonatoms, the alkyl group having 1 to 6 carbon atoms, and the alkoxy grouphaving 1 to 6 carbon atoms are fluorine (F), chlorine (Cl), bromine(Br), iodine (I), a cyano group (CN), a trifluoromethylsulfonyl group(SO₂CF₃), a trifluoromethyl group (CF₃), a nitro group (NO₂), anisothiocyanate group (NCS), and a pentafluorosulfanyl group (SF₅).

Another embodiment of the present invention is a dioxolane derivativerepresented by General Formula (G3).

In General Formula (G3), Ar¹ and Ar² independently represent hydrogen, asubstituted or unsubstituted aryl group having 6 to 12 carbon atoms, asubstituted or unsubstituted cycloalkyl group having 3 to 12 carbonatoms, or a substituted or unsubstituted cycloalkenyl group having 4 to12 carbon atoms; Ar²³ represents a substituted or unsubstituted pyrenylgroup or a substituted or unsubstituted naphthyl group; a¹ and a²independently represent a substituted or unsubstituted alkylene grouphaving 1 to 4 carbon atoms or a single bond; and R¹ and R² independentlyrepresent hydrogen, a substituted or unsubstituted alkyl group having 1to 6 carbon atoms, a substituted or unsubstituted alkoxy group having 1to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6to 12 carbon atoms.

Furthermore, in General Formula (G3), examples of the substituents onthe aryl group having 6 to 12 carbon atoms, the cycloalkyl group having3 to 12 carbon atoms, the cycloalkenyl group having 4 to 12 carbonatoms, the pyrenyl group, the naphthyl group, the alkylene group having1 to 4 carbon atoms, the alkyl group having 1 to 6 carbon atoms, and thealkoxy group having 1 to 6 carbon atoms are fluorine (F), chlorine (Cl),bromine (Br), iodine (I), a cyano group (CN), a trifluoromethylsulfonylgroup (SO₂CF₃), a trifluoromethyl group (CF₃), a nitro group (NO₂), anisothiocyanate group (NCS), and a pentafluorosulfanyl group (SF₅).

Another embodiment of the present invention is a dioxolane derivativerepresented by Structural Formula (200).

Another embodiment of the present invention is a dioxolane derivativerepresented by Structural Formula (201).

Another embodiment of the invention disclosed herein is a noveldioxolane derivative represented by General Formula (G4). The dioxolanederivative can function as a chiral material in a liquid crystalcomposition.

In General Formula (G4), Ar⁴¹ represents a substituted or unsubstitutedarylene group having 6 to 12 carbon atoms, a substituted orunsubstituted cycloalkylene group having 3 to 12 carbon atoms, or asubstituted or unsubstituted cycloalkenylene group having 4 to 12 carbonatoms; n represents any of 0 to 3; R¹ and R² independently representhydrogen, a substituted or unsubstituted alkyl group having 1 to 6carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 6carbon atoms, or a substituted or unsubstituted aryl group having 6 to12 carbon atoms; R³ represents hydrogen, a substituted or unsubstitutedalkyl group having 1 to 6 carbon atoms, or a substituted orunsubstituted alkoxy group having 1 to 6 carbon atoms (when n is 0, R³does not include hydrogen).

In General Formula (G4), examples of the substituents on the arylenegroup having 6 to 12 carbon atoms, the cycloalkylene group having 3 to12 carbon atoms, the cycloalkenylene group having 4 to 12 carbon atoms,the alkyl group having 1 to 6 carbon atoms, the alkoxy group having 1 to6 carbon atoms, and the aryl group having 6 to 12 carbon atoms arefluorine (F), chlorine (Cl), bromine (Br), iodine (I), a cyano group(CN), a trifluoromethylsulfonyl group (SO₂CF₃), a trifluoromethyl group(CF₃), a nitro group (NO₂), an isothiocyanate group (NCS), and apentafluorosulfanyl group (SF₅).

Another embodiment of the present invention is a dioxolane derivativerepresented by the following Structural Formula (300).

Another embodiment of the present invention is a liquid crystalcomposition including at least a nematic liquid crystal and any of theabove dioxolane derivatives.

Another embodiment of the present invention is a liquid crystalcomposition exhibiting a blue phase and including at least a nematicliquid crystal and any of the above dioxolane derivatives. Note that ablue phase is exhibited in a liquid crystal composition having strongtwisting power and has a double twist structure. The liquid crystalcomposition that can exhibit a blue phase shows a cholesteric phase, acholesteric blue phase, an isotropic phase, or the like depending onconditions.

Indicators of the strength of twisting power include the helical pitch,the selective reflection wavelength, HTP (helical twisting power), andthe diffraction wavelength.

When the twisting power of the liquid crystal composition that exhibitsa blue phase is strong, the transmittance of the liquid crystalcomposition in the absence of an applied voltage (at an applied voltageof 0 V) can be reduced by addition of a small amount of chiral material.In addition, the liquid crystal can be easily operated by application ofvoltage, whereby high transmittance can be achieved. Thus, a liquidcrystal display device including the liquid crystal composition canexhibit high contrast.

The liquid crystal composition of one embodiment of the presentinvention includes at least the dioxolane derivative represented byGeneral Formula (G1), (G2), (G3), or (G4) and a nematic liquid crystal.The dioxolane derivative represented by General Formula (G1), (G2),(G3), or (G4) has chiral centers; therefore, when included in a liquidcrystal composition, the dioxolane derivative can serve as a chiralmaterial that induces twist of the liquid crystal composition to causehelical orientation.

In addition, since the dioxolane derivative represented by GeneralFormula (G1), (G2), (G3), or (G4) is a chiral material with strongtwisting power, the proportion thereof in a liquid crystal compositioncan be lower than or equal to 15 wt %, lower than or equal to 10 wt %,or lower than or equal to 8 wt %. In general, when a large amount ofchiral material is added in order to improve the twisting power of theliquid crystal composition, driving voltage for driving a liquid crystalelement including the liquid crystal composition tends to increase.However, in the liquid crystal composition of one embodiment of thepresent invention, the amount of chiral material can be reduced, so thatan increase in the driving voltage of the liquid crystal element can besuppressed. Thus, a reduction in power consumption of the liquid crystaldisplay device can be achieved.

One embodiment of the present invention includes a liquid crystalelement, and a liquid crystal display device, an electronic applianceeach including the above liquid crystal composition.

With one embodiment of the present invention, a novel dioxolanederivative that can be used for various liquid crystal display devicescan be provided. A novel liquid crystal composition using the dioxolanederivative can be provided. Another object is to provide a liquidcrystal element and a liquid crystal display device each including theliquid crystal composition can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings:

FIGS. 1A and 1B are conceptual diagrams each illustrating a liquidcrystal element;

FIGS. 2A and 2B illustrate one mode of a liquid crystal display device;

FIGS. 3A to 3D each illustrate one mode of an electrode structure of aliquid crystal display device;

FIGS. 4A1, 4A2, and 4B illustrate liquid crystal display modules;

FIGS. 5A to 5F each illustrate an electronic appliance;

FIGS. 6A and 6B are ¹H NMR charts of(4R,5R)-2,2-dimethyl-α,α,α′,α′-tetra[4-(trans-4-n-pentylcyclohexyl)phenyl]-1,3-dioxolane-4,5-dimethanol (R-DOL-PC5);

FIG. 7 is a ¹H NMR chart of R-DOL-PC5;

FIGS. 8A and 8B are ¹H NMR charts of(4R,5R)-2,2-dimethyl-α,α,α′,α′-tetra[4′-(n-hexyl-1-oxy)-1,1-biphenyl-4-yl]-1,3-dioxolane-4,5-dimethanol (R-DOL-PPO6);

FIG. 9 is a ¹H NMR chart of R-DOL-PPO6;

FIGS. 10A and 10B are ¹H NMR charts of(4R,5R)-2,2-dimethyl-α,α,α′,α′-tetra[4′-(n-pentyl)-1,1-biphenyl-4-yl]-1,3-dioxolane-4,5-dimethanol(R-DOL-PP5);

FIG. 11 is a ¹H NMR chart of R-DOL-PP5;

FIGS. 12A and 12B are ¹H NMR charts of(4R,5R)-2,2-dimethyl-α,α,α′,α′-tetra(naphthalen-1-yl)-1,3-dioxolane-4,5-dimethanol(R-DOL-αNp);

FIG. 13 is a ¹H NMR chart of R-DOL-αNp;

FIGS. 14A and 14B are ¹H NMR charts of(4R,5R)-2,2-dimethyl-α,α,α′,α′-tetra(pyren-1-yl)-1,3-dioxolane-4,5-dimethanol(R-DOL-Prna);

FIG. 15 is a ¹H NMR chart of R-DOL-Prna;

FIGS. 16A and 16B are ¹H NMR charts of(4R,5R)-2,2-dimethyl-1,3-dioxolane-4,5-dimethanolbis{4-[4-(n-hexyl-1-oxy)phenyl]benzoate} (R-DOL-1EPPO6); and

FIG. 17 is a ¹H NMR chart of R-DOL-1EPPO6.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the invention disclosed in this specification will bedescribed below with reference to the accompanying drawings. Note thatthe invention disclosed in this specification is not limited to thefollowing description, and it is easily understood by those skilled inthe art that modes and details of the invention can be modified invarious ways. Therefore, the invention disclosed in this specificationis not construed as being limited to the description of the followingembodiments or examples.

(Embodiment 1)

In this embodiment, a novel dioxolane derivative of one embodiment ofthe present invention will be described.

One embodiment of the present invention is a dioxolane derivativerepresented by General Formula (G1).

In General Formula (G1), Ar¹ and Ar² independently represent hydrogen, asubstituted or unsubstituted aryl group having 6 to 12 carbon atoms, asubstituted or unsubstituted cycloalkyl group having 3 to 12 carbonatoms, or a substituted or unsubstituted cycloalkenyl group having 4 to12 carbon atoms; Ar³ and Ar⁴ independently represent a substituted orunsubstituted arylene group having 6 to 12 carbon atoms, a substitutedor unsubstituted cycloalkylene group having 3 to 12 carbon atoms, or asubstituted or unsubstituted cycloalkenylene group having 4 to 12 carbonatoms; m represents any of 1 to 3, and n represents any of 0 to 3; a¹and a independently represent a substituted or unsubstituted alkylenegroup having 1 to 4 carbon atoms or a single bond; R¹ and R²independently represent hydrogen, a substituted or unsubstituted alkylgroup having 1 to 6 carbon atoms, a substituted or unsubstituted alkoxygroup having 1 to 6 carbon atoms, or a substituted or unsubstituted arylgroup having 6 to 12 carbon atoms; and R³ represents hydrogen, asubstituted or unsubstituted alkyl group having 1 to 6 carbon atoms, ora substituted or unsubstituted alkoxy group having 1 to 6 carbon atoms.

In General Formulae (G1), examples of the substituents on the aryl grouphaving 6 to 12 carbon atoms, the cycloalkyl group having 3 to 12 carbonatoms, the cycloalkenyl group having 4 to 12 carbon atoms, the arylenegroup having 6 to 12 carbon atoms, the cycloalkylene group having 3 to12 carbon atoms, the cycloalkenylene group having 4 to 12 carbon atoms,the alkylene group having 1 to 4 carbon atoms, the alkyl group having 1to 6 carbon atoms, and the alkoxy group having 1 to 6 carbon atoms arefluorine (F), chlorine (Cl), bromine (Br), iodine (I), a cyano group(CN), a trifluoromethylsulfonyl group (SO₂CF₃), a trifluoromethyl group(CF₃), a nitro group (NO₂), an isothiocyanate group (NCS), and apentafluorosulfanyl group (SF₅).

Specific examples of the dioxolane derivative represented by GeneralFormula (G1) include the dioxolane derivatives represented by StructuralFormulae (100) to (109). However, the present invention is not limitedto these examples.

A variety of reactions can be applied to a method for synthesizing thedioxolane derivative of this embodiment. The following is an example ofa method for synthesizing the dioxolane derivative represented byGeneral Formula (G1).

The dioxolane derivative represented by General Formula (G1) can besynthesized by the reactions represented by the following Scheme (K1-1).

The reaction of a 1,3-dioxolane-4,5-dicarboxylic ester (compound 11)with four equivalents of a Grignard reagent (compound 12) gives acompound 13 having a 1,3-dioxolane skeleton. The hydroxyl groups ofcompound 13 are converted to alkoxy groups through the Williamson ethersynthesis reaction or the like by using organic halides (compounds 14and 15; compounds 14 and 15 may be the same), leading to the targetdioxolane derivative (General Formula (G1)) (Scheme (K1-1)).

The dioxolane derivative represented by General Formula (G1) has chiralcenters; therefore, when included in a liquid crystal composition, thedioxolane derivative can serve as a chiral material that induces twistof the liquid crystal composition to cause helical orientation.

For example, the liquid crystal composition including the dioxolanederivative represented by General Formula (G1) as a chiral material canbe used for a liquid crystal display device in a lateral electric fieldmode such as a blue phase mode, a liquid crystal display device in avertical electric field mode such as a TN mode or a cholesteric liquidcrystal mode, and the like.

The structures, methods, and the like described in this embodiment canbe combined as appropriate with any of the structures, methods, and thelike described in the other embodiments.

(Embodiment 2)

In this embodiment, a novel dioxolane derivative of one embodiment ofthe present invention will be described.

One embodiment of the present invention is a dioxolane derivativerepresented by General Formula (G2).

In General Formula (G2), Ar¹ and Ar² independently represent hydrogen, asubstituted or unsubstituted aryl group having 6 to 12 carbon atoms, asubstituted or unsubstituted cycloalkyl group having 3 to 12 carbonatoms, or a substituted or unsubstituted cycloalkenyl group having 4 to12 carbon atoms; Ar²³ and Ar²⁴ independently represent a substituted orunsubstituted pyrenyl group or a substituted or unsubstituted naphthylgroup; a¹ and a² independently represent a substituted or unsubstitutedalkylene group having 1 to 4 carbon atoms or a single bond; and R¹ andR² independently represent hydrogen, a substituted or unsubstitutedalkyl group having 1 to 6 carbon atoms, a substituted or unsubstitutedalkoxy group having 1 to 6 carbon atoms, or a substituted orunsubstituted aryl group having 6 to 12 carbon atoms.

In General Formula (G2), examples of the substituents on the aryl grouphaving 6 to 12 carbon atoms, the cycloalkyl group having 3 to 12 carbonatoms, the cycloalkenyl group having 4 to 12 carbon atoms, the pyrenylgroup, the naphthyl group, the alkylene group having 1 to 4 carbonatoms, the alkyl group having 1 to 6 carbon atoms, and the alkoxy grouphaving 1 to 6 carbon atoms are fluorine (F), chlorine (Cl), bromine(Br), iodine (I), a cyano group (CN), a trifluoromethylsulfonyl group(SO₂CF₃), a trifluoromethyl group (CF₃), a nitro group (NO₂), anisothiocyanate group (NCS), and a pentafluorosulfanyl group (SF₅).

In General Formula (G2), Ar²³ and Ar²⁴ may be the same; in which casethe dioxolane derivative is represented by General Formula (G3).

Specific examples of the dioxolane derivative represented by GeneralFormula (G2) include the dioxolane derivatives represented by StructuralFormulae (200) to (211). However, the present invention is not limitedto these examples.

A variety of reactions can be applied to a method for synthesizing thedioxolane derivative of this embodiment. The following is an example ofa method for synthesizing the dioxolane derivative represented byGeneral Formula (G2).

The dioxolane derivative represented by General Formula (G2) can besynthesized by the reactions represented by the following Scheme (K2-1).

The reaction of a 1,3-dioxolane-4,5-dicarboxylic ester (compound 21)with two equivalents of a Grignard reagent (compound 22) gives acompound 23 having a 1,3-dioxolane skeleton. Then, compound 23 issubjected to the reaction with two equivalents of a Grignard reagent(compound 24) to obtain a compound having a 1,3-dioxolane skeleton(compound 25). The hydroxyl group of compound 25 is converted to analkoxy group through the Williamson ether synthesis reaction or the likeby using organic halides (compounds 26 and 27; compounds 26 and 27 maybe the same), leading to the target dioxolane derivative (GeneralFormula (G2)) (Scheme (K2-1)).

The dioxolane derivative represented by General Formula (G2) or (G3) haschiral centers; therefore, when included in a liquid crystalcomposition, the dioxolane derivative can serve as a chiral materialthat induces twist of the liquid crystal composition to cause helicalorientation.

For example, the liquid crystal composition including the dioxolanederivative represented by General Formula (G2) as a chiral material canbe used for a liquid crystal display device in a lateral electric fieldmode such as a blue phase mode, a liquid crystal display device in avertical electric field mode such as a TN mode or a cholesteric liquidcrystal mode, and the like.

The structures, methods, and the like described in this embodiment canbe combined as appropriate with any of the structures, methods, and thelike described in the other embodiments.

(Embodiment 3)

In this embodiment, a novel dioxolane derivative of one embodiment ofthe present invention will be described.

One embodiment of the present invention is a dioxolane derivativerepresented by General Formula (G4).

In General Formula (G4), Ar⁴¹ represents a substituted or unsubstitutedarylene group having 6 to 12 carbon atoms, a substituted orunsubstituted cycloalkylene group having 3 to 12 carbon atoms, or asubstituted or unsubstituted cycloalkenylene group having 4 to 12 carbonatoms; n represents any of 0 to 3; R¹ and R² independently representhydrogen, a substituted or unsubstituted alkyl group having 1 to 6carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 6carbon atoms, or a substituted or unsubstituted aryl group having 6 to12 carbon atoms; and R³ represents hydrogen, a substituted orunsubstituted alkyl group having 1 to 6 carbon atoms, or a substitutedor unsubstituted alkoxy group having 1 to 6 carbon atoms (when n is 0,R³ does not include hydrogen).

In General Formula (G4), examples of the substituents on the arylenegroup having 6 to 12 carbon atoms, the cycloalkylene group having 3 to12 carbon atoms, the cycloalkenylene group having 4 to 12 carbon atoms,the alkyl group having 1 to 6 carbon atoms, the alkoxy group having 1 to6 carbon atoms, and the aryl group having 6 to 12 carbon atoms arefluorine (F), chlorine (Cl), bromine (Br), iodine (I), a cyano group(CN), a trifluoromethylsulfonyl group (SO₂CF₃), a trifluoromethyl group(CF₃), a nitro group (NO₂), an isothiocyanate group (NCS), and apentafluorosulfanyl group (SF₅).

Specific examples of the dioxolane derivative represented by GeneralFormula (G4) include the dioxolane derivatives represented by StructuralFormulae (300) to (309). However, the present invention is not limitedto these examples.

A variety of reactions can be applied to a method for synthesizing thedioxolane derivative of this embodiment. The following is an example ofa method for synthesizing the dioxolane derivative represented byGeneral Formula (G4).

The dioxolane derivative represented by General Formula (G4) can besynthesized by the reactions represented by the following Scheme (K3-1).

The esterification of a 1,3-dioxolane-4,5-dimethanol (compound 41) withtwo equivalents of a carboxylic acid (compound 42) gives the targetdioxolane derivative (General Formula (G4)) (Scheme (K3-1)).

The dioxolane derivative represented by General Formula (G4) has chiralcenters; therefore, when included in a liquid crystal composition, thedioxolane derivative can serve as a chiral material that induces twistof the liquid crystal composition to cause helical orientation.

For example, the liquid crystal composition including the dioxolanederivative represented by General Formula (G4) as a chiral material canbe used for a liquid crystal display device in a lateral electric fieldmode such as a blue phase mode, a liquid crystal display device in avertical electric field mode such as a TN mode or a cholesteric liquidcrystal mode, and the like.

The structures, methods, and the like described in this embodiment canbe combined as appropriate with any of the structures, methods, and thelike described in the other embodiments.

(Embodiment 4)

In this embodiment, a liquid crystal composition including any of thedioxolane derivatives described in Embodiments 1 to 3, each of which isone embodiment of the present invention, and a liquid crystal element orliquid crystal display device each including the liquid crystalcomposition will be described with reference to FIGS. 1A and 1B.

The liquid crystal composition of this embodiment includes a nematicliquid crystal and any of the dioxolane derivatives described inEmbodiments 1 to 3.

As described above, the dioxolane derivative represented by GeneralFormula (G1), (G2), (G3), or (G4) can serve as a chiral material. Inaddition, since the dioxolane derivative represented by General Formula(G1), (G2), (G3), or (G4) is a chiral material with strong twistingpower, the proportion thereof in a liquid crystal composition can belower than or equal to 15 wt %, lower than or equal to 10 wt %, or lowerthan or equal to 8 wt %.

There is no particular limitation on the nematic liquid crystal includedin the liquid crystal composition of one embodiment of the presentinvention, and examples thereof include a biphenyl-based compound, aterphenyl-based compound, a phenylcyclohexyl-based compound, abiphenylcyclohexyl-based compound, a phenylbicyclohexyl-based compound,a phenyl benzoate-based compound, a phenyl cyclohexylbenzoate-basedcompound, a phenyl benzoate-based compound, a phenylbicyclohexylcarboxylate-based compound, an azomethine-based compound, anazo-based compound, an azoxy-based compound, a stilbene-based compound,a bicyclohexyl-based compound, a phenylpyrimidine-based compound, abiphenylpyrimidine-based compound, a pyrimidine-based compound, and adiphenylacetylene-based compound.

Note that the liquid crystal composition of this embodiment includes anematic liquid crystal and the dioxolane derivative represented byGeneral Formula (G1), (G2), (G3), or (G4), and may be a liquid crystalcomposition which exhibits a blue phase. A blue phase is opticallyisotropic and thus has no viewing angle dependence. Consequently, analignment film is not necessarily formed; thus, image quality of adisplay device can be improved and a manufacturing cost can be reduced.

In the case where the liquid crystal composition described in thisembodiment exhibits a blue phase, it is preferable that a polymerizablemonomer be added to a liquid crystal composition and polymerstabilization treatment be performed in order to broaden the temperaturerange within which a blue phase is exhibited in a liquid crystal displaydevice. As the polymerizable monomer, for example, a thermopolymerizable(thermosetting) oligomers which can be polymerized by heat, aphotopolymerizable (photocurable) oligomers which can be polymerized bylight, and the like can be used in addition to vinyl monomers.

The polymerizable vinyl monomer may be a monofunctional monomer such asan acrylate or a methacrylate; a polyfunctional monomer such as adiacrylate, a triacrylate, a dimethacrylate, or a trimethacrylate; or amixture thereof. The polymerizable monomer may have liquidcrystallinity, non-liquid crystallinity, or a mixture of them.

A polymerization initiator may be added to the liquid crystalcomposition when the polymer stabilization treatment is carried out. Asthe polymerization initiator, a radical polymerization initiator whichgenerates radicals by light irradiation or heating, an acid generatorwhich generates an acid by light irradiation or heating, or a basegenerator which generates a base by light irradiation or heating may beused.

For example, polymer stabilization treatment can be performed in such amanner that a polymerizable monomer and a photopolymerization initiatorare added to the liquid crystal composition and the liquid crystalcomposition is irradiated with light

This polymer stabilization treatment may be performed in a state that aliquid crystal composition exhibits an isotropic phase or in a statethat a liquid crystal composition exhibits a blue phase under thetemperature control. A temperature at which the phase changes from ablue phase to an isotropic phase when the temperature is increased, or atemperature at which the phase changes from an isotropic phase to a bluephase when the temperature is decreased is referred to as the phasetransition temperature between a blue phase and an isotropic phase. Forexample, the polymer stabilization treatment can be performed in thefollowing manner: after a liquid crystal composition to which aphotopolymerizable monomer is added is heated to exhibit an isotropicphase, the temperature of the liquid crystal composition is graduallydecreased until the phase changes to a blue phase, and then, lightirradiation is performed while the temperature at which a blue phase isexhibited is kept.

FIGS. 1A and 1B illustrate examples of a liquid crystal element and aliquid crystal display device of embodiments of the present invention.

A liquid crystal element in this embodiment includes, between a pair ofelectrode layers (a pixel electrode layer 230 and a common electrodelayer 232 to be applied with different potentials), a liquid crystalcomposition 208 which includes the dioxolane derivative represented byGeneral Formula (G1), (G2), (G3), or (G4) in Embodiments 1 to 3 and anematic liquid crystal. Note that the liquid crystal composition 208 mayinclude an organic resin.

FIGS. 1A and 1B each illustrate a liquid crystal display element or aliquid crystal display device in which the liquid crystal composition208 which includes a nematic liquid crystal and the dioxolane derivativerepresented by General Formula (G1), (G2), (G3), or (G4) is providedbetween a first substrate 200 and a second substrate 201. A differencebetween the liquid crystal element and the liquid crystal display devicein FIG. 1A and those in FIG. 1B is positions of the pixel electrodelayer 230 and the common electrode layer 232 with respect to the liquidcrystal composition 208.

In the liquid crystal element and the liquid crystal display deviceillustrated in FIG. 1A, the pixel electrode layer 230 and the commonelectrode layer 232 are each provided between the first substrate 200and the liquid crystal composition 208 and adjacent to each other. Thestructure of FIG. 1A can be driven so that the gray scale is controlledby generating an electric field substantially parallel (i.e., in alateral direction) to a substrate to orientate liquid crystal moleculesin a plane parallel to the substrate.

Note that a liquid crystal composition which includes a nematic liquidcrystal and the dioxolane derivative of one embodiment of the presentinvention, which is represented by General Formula (G1), (G2), (G3), or(G4), may be a liquid crystal composition exhibiting a blue phase. Thestructure illustrated in FIG. 1A is preferable in the case where aliquid crystal composition exhibiting a blue phase is used as the liquidcrystal composition 208. The liquid crystal composition exhibiting ablue phase is capable of quick response. Thus, a high-performance liquidcrystal element and a high-performance liquid crystal display device canbe provided. Additionally, because the orientation control is conductedwith the IPS mode, it is possible to obtain a wide viewing anglecompared with the traditional devices in which the orientation iscontrolled by the TN mode or VA mode.

For example, the quick response of such a liquid crystal compositionexhibiting a blue phase allows the application of a successive additivecolor mixing method (a field sequential method) or a three-dimensionaldisplay method. In the successive additive color mixing method,light-emitting diodes (LEDs) of RGB or the like are arranged in abacklight unit and color display is performed by time division. In thethree-dimensional display method, a shutter glasses system is used inwhich images for a right eye and images for a left eye are alternatelyviewed by time division.

In the liquid crystal element and the liquid crystal display deviceillustrated in FIG. 1B, the pixel electrode layer 230 and the commonelectrode layer 232 are provided on the first substrate 200 side and thesecond substrate 201 side, respectively, with the liquid crystalcomposition 208 interposed therebetween. With the structure of FIG. 1B,the gray scale can be controlled by generating an electric fieldsubstantially perpendicular to a substrate to orientate liquid crystalmolecules in a plane perpendicular to the substrate. An alignment film202 a may be provided between the liquid crystal composition 208 and thepixel electrode layer 230 and an alignment film 202 b may be providedbetween the liquid crystal composition 208 and the common electrodelayer 232. A liquid crystal composition which includes a nematic liquidcrystal and the dioxolane derivative of one embodiment of the presentinvention can be used for liquid crystal elements with a variety ofstructures and liquid crystal display devices in a variety of displaymodes (e.g., a TN mode, a cholesteric liquid crystal mode, or a VAmode).

Although not illustrated in FIGS. 1A and 1B, an optical film such as apolarizing plate, a retardation plate, an anti-reflection film, or thelike may be provided as appropriate. For example, circular polarizationby the polarizing plate and the retardation plate may be used. Inaddition, a backlight or the like can be used as a light source.

In this specification, the first substrate can be provided with asemiconductor element (e.g., a transistor) or a pixel electrode layer.In this case, the first substrate is referred to as an elementsubstrate, and the second substrate which faces the element substratewith a liquid crystal composition interposed therebetween is referred toas a counter substrate.

As a liquid crystal display device of one embodiment of the presentinvention, a transmissive liquid crystal display device in which displayis performed by transmission of light from a light source, a reflectiveliquid crystal display device in which display is performed byreflection of incident light, or a transflective liquid crystal displaydevice in which a transmissive type and a reflective type are combinedcan be provided.

In the case of the transmissive liquid crystal display device, a pixelelectrode layer and a common electrode layer, which are provided in alight-transmitting pixel region, as well as a first substrate, a secondsubstrate, and other components such as an insulating film and aconductive film have a light-transmitting property. In the liquidcrystal display device having the structure illustrated in FIG. 1A, itis preferable that the pixel electrode layer and the common electrodelayer have a light-transmitting property; however, if an opening isprovided, a non-light-transmitting material such as a metal film may beused depending on the shape.

On the other hand, in the case of the reflective liquid crystal displaydevice, a reflective component which reflects light transmitted throughthe liquid crystal composition (e.g., a reflective film or substrate)may be provided on the side opposite to the viewing side of the liquidcrystal composition. Therefore, a substrate, an insulating film, and aconductive film which are provided between the viewing side and thereflective component and through which light is transmitted have alight-transmitting property. Note that in this specification, alight-transmitting property refers to a property of transmitting atleast visible light. In the liquid crystal display device having thestructure illustrated in FIG. 1B, the pixel electrode layer or thecommon electrode layer on the side opposite to the viewing side may havea light-reflecting property so that it can be used as a reflectivecomponent.

The pixel electrode layer 230 and the common electrode layer 232 may beformed with the use of one or more of the following: indium tin oxide(ITO); a conductive material in which zinc oxide (ZnO) is mixed intoindium oxide; a conductive material in which silicon oxide (SiO₂) ismixed into indium oxide; indium oxide containing tungsten oxide; indiumzinc oxide containing tungsten oxide; indium oxide containing titaniumoxide; indium tin oxide containing titanium oxide; graphene; metals suchas tungsten (W), molybdenum (Mo), zirconium (Zr), hafnium (Hf), vanadium(V), niobium (Nb), tantalum (Ta), chromium (Cr), cobalt (Co), nickel(Ni), titanium (Ti), platinum (Pt), aluminum (Al), copper (Cu), andsilver (Ag); alloys thereof; and metal nitrides thereof.

As the first substrate 200 and the second substrate 201, a glasssubstrate of barium borosilicate glass, aluminoborosilicate glass, orthe like, a quartz substrate, a plastic substrate, or the like can beused. Note that in the case of the reflective liquid crystal displaydevice, a metal substrate such as an aluminum substrate or a stainlesssteel substrate may be used as a substrate on the side opposite to theviewing side.

With the use of the dioxolane derivative represented by General Formula(G1), (G2), (G3), or (G4) as a chiral material in a liquid crystalcomposition, the amount of chiral material added to the liquid crystalcomposition can be small. Therefore, by using the liquid crystalcomposition, a liquid crystal element or liquid crystal display devicethat can be driven at a low driving voltage can be provided, and areduction in power consumption of the liquid crystal display device canbe achieved.

Furthermore, the liquid crystal composition of one embodiment of thepresent invention can exhibit a blue phase and respond quickly.Therefore, by using the liquid crystal composition, a high-performanceliquid crystal element or liquid crystal display device can be provided.

The structures, methods, and the like described in this embodiment canbe combined as appropriate with any of the structures, methods, and thelike described in the other embodiments.

(Embodiment 5)

As a liquid crystal display device according to one embodiment of thepresent invention, a passive matrix liquid crystal display device and anactive matrix liquid crystal display device can be provided. In thisembodiment, an example of an active matrix liquid crystal display devicewill be described with reference to FIGS. 2A and 2B and FIGS. 3A to 3D.

FIG. 2A is a plan view of the liquid crystal display device andillustrates one pixel. FIG. 2B is a cross-sectional view taken alongline X1-X2 in FIG. 2A.

In FIG. 2A, a plurality of source wiring layers (including a wiringlayer 405 a) is arranged so as to be parallel to (extend in the verticaldirection in the drawing) and apart from each other. A plurality of gatewiring layers (including a gate electrode layer 401) is provided toextend in a direction substantially perpendicular to the source wiringlayers (the horizontal direction in the drawing) and to be apart fromeach other. Common wiring layers 408 are provided adjacent to therespective plurality of gate wiring layers and extend in a directionsubstantially parallel to the gate wiring layers, that is, in adirection substantially perpendicular to the source wiring layers (thehorizontal direction in the drawing). A roughly rectangular space issurrounded by the source wiring layers, the common wiring layers 408,and the gate wiring layers. In this space, a pixel electrode layer and acommon electrode layer of the liquid crystal display device areprovided. A transistor 420 for driving the pixel electrode layer isprovided at an upper left corner of the drawing. A plurality of pixelelectrode layers and a plurality of transistors are arranged in matrix.

In the liquid crystal display device of FIGS. 2A and 2B, a firstelectrode layer 447 which is electrically connected to the transistor420 serves as a pixel electrode layer, while a second electrode layer446 which is electrically connected to the common wiring layer 408serves as a common electrode layer. Note that a capacitor is formed bythe first electrode layer and the common wiring layer. Although thecommon electrode layer can operate in a floating state (an electricallyisolated state), the potential of the common electrode layer may be setto a fixed potential, preferably to a potential around a commonpotential (an intermediate potential of an image signal which istransmitted as data) in such a level as not to generate flickers.

It is possible to employ a driving method in which the gray scale iscontrolled by generating an electric field substantially parallel (i.e.,in a lateral direction) to a substrate to orientate liquid crystalmolecules in a plane parallel to the substrate. For such a method, anelectrode structure used in an IPS mode as illustrated in FIGS. 2A and2B and FIGS. 3A to 3D can be employed.

In a lateral electric field mode such as an IPS mode, a first electrodelayer (e.g., a pixel electrode layer a voltage of which is controlled ineach pixel) and a second electrode layer (e.g., a common electrode layerto which a common voltage is supplied in all pixels), each of which hasan opening pattern, are located below a liquid crystal composition.Therefore, the first electrode layer 447 and the second electrode layer446, one of which is a pixel electrode layer and the other is a commonelectrode layer, are formed over a first substrate 441, and at least oneof the first electrode layer and the second electrode layer is formedover an insulating film. The first electrode layer 447 and the secondelectrode layer 446 have a variety of shapes. For example, they can havean opening portion, a bent portion, branched portion, or a comb-shapedportion. In order to generate an electric field substantially parallelto a substrate between the first electrode layer 447 and the secondelectrode layer 446, an arrangement is avoided in which they have thesame shape and completely overlap with each other.

The first electrode layer 447 and the second electrode layer 446 mayhave a structure applicable in an FFS mode. In a lateral electric fieldmode such as an FFS mode, a first electrode layer (e.g., a pixelelectrode layer a voltage of which is controlled in each pixel) havingan opening pattern is located below a liquid crystal composition, andfurther, a second electrode layer (e.g., a common electrode layer towhich a common voltage is supplied in all pixels) having a board shapeis located below the opening pattern. In this case, the first electrodelayer and the second electrode layer, one of which is a pixel electrodelayer and the other of which is a common electrode layer, are formedover the first substrate 441, and the pixel electrode layer and thecommon electrode layer are stacked with an insulating film (or aninterlayer insulating layer) interposed therebetween. One of the pixelelectrode layer and the common electrode layer is formed below theinsulating film (or the interlayer insulating layer) and has a boardshape, whereas the other is formed above the insulating film (or theinterlayer insulating layer) and has various shapes including an openingportion, a bent portion, a branched portion, or a comb-like portion. Inorder to generate an electric field slant to a substrate between thefirst electrode layer 447 and the second electrode layer 446, anarrangement is avoided in which they have the same shape and completelyoverlap with each other.

The liquid crystal composition including the dioxolane derivativerepresented by General Formula (G1), (G2), (G3), or (G4) shown inEmbodiments 1 to 3 and a nematic liquid crystal is used as a liquidcrystal composition 444. The liquid crystal composition 444 may furtherinclude an organic resin. In this embodiment, the liquid crystalcomposition 444 includes the dioxolane derivative represented by GeneralFormula (G1), (G2), (G3), or (G4) and a nematic liquid crystal andexhibits a blue phase. The liquid crystal composition 444 is formed byperforming the polymer stabilization treatment in a state that liquidcrystal composition 444 exists in a blue phase.

With a lateral electric field generated between the first electrodelayer 447 and the second electrode layer 446, liquid crystal of theliquid crystal composition 444 is controlled. Hence, a wide viewingangle can be obtained.

FIGS. 3A to 3D show other examples of the first electrode layer 447 andthe second electrode layer 446. As illustrated in top views of FIGS. 3Ato 3D, first electrode layers 447 a to 447 d and second electrode layers446 a to 446 d are staggered. In FIG. 3A, the first electrode layer 447a and the second electrode layer 446 a have an opening with a wavelikeshape. In FIG. 3B, the first electrode layer 447 b and the secondelectrode layer 446 b have a shape with concentric circular openings. InFIG. 3C, the first electrode layer 447 c and the second electrode layer446 c have a comb-shape and partially overlap with each other. In FIG.3D, the first electrode layer 447 d and the second electrode layer 446 dhave a comb-shape in which the electrode layers are engaged with eachother. In the case where the first electrode layers 447 a, 447 b, and447 c overlap with the second electrode layers 446 a, 446 b, and 446 c,respectively, as illustrated in FIGS. 3A to 3C, an insulating film isformed between the first electrode layer 447 and the second electrodelayer 446 so that the first electrode layer 447 and the second electrodelayer 446 are formed over different films.

Since the second electrode layer 446 has an opening pattern, they areillustrated as a divided plurality of electrode layers in thecross-sectional view of FIG. 2B. The same applies to the other drawingsof this specification.

The transistor 420 is an inverted staggered thin film transistor inwhich the gate electrode layer 401, a gate insulating layer 402, asemiconductor layer 403, and wiring layers 405 a and 405 b whichfunction as a source electrode layer and a drain electrode layer areformed over the first substrate 441 which has an insulating surface.

There is no particular limitation on a structure of a transistor thatcan be used for a liquid crystal display device disclosed in thisspecification. For example, a staggered type or a planar type having atop-gate structure or a bottom-gate structure can be employed. Thetransistor may have a single-gate structure in which one channelformation region is formed, a double-gate structure in which two channelformation regions are formed, or a triple-gate structure in which threechannel formation regions are formed. Alternatively, the transistor mayhave a dual gate structure including two gate electrode layerspositioned over and below a channel region with a gate insulating layerprovided therebetween.

An insulating film 407 that is in contact with the semiconductor layer403, and an insulating film 409 are provided to cover the transistor420. An interlayer film 413 is stacked over the insulating film 409.

The first substrate 441 and a second substrate 442 that is a countersubstrate are firmly attached to each other with a sealant with theliquid crystal composition 444 interposed therebetween. The liquidcrystal composition 444 can be formed by a dispenser method (a droppingmethod), or an injection method by which a liquid crystal composition444 is injected using capillary action or the like after the firstsubstrate 441 is attached to the second substrate 442.

As the sealant, typically, a visible light curable resin, a UV curableresin, or a thermosetting resin is preferably used. Typically, anacrylic resin, an epoxy resin, an amine resin, or the like can be used.Further, a filler or a coupling agent may be included in the sealant.

In this embodiment, a polarizing plate 443 a is provided on the outerside (on the side opposite to the liquid crystal composition 444) of thefirst substrate 441, and a polarizing plate 443 b is provided on theouter side (on the side opposite to the liquid crystal composition 444)of the second substrate 442. In addition to the polarizing plates, anoptical film such as a retardation plate or an anti-reflection film maybe provided. For example, circular polarization plate formed by thepolarizing plate and the retardation plate may be used. Through theabove-described process, a liquid crystal display device is completed.

Although not illustrated, a backlight, a sidelight, or the like may beused as a light source. Light source is provided so that light whichpasses through the first substrate 441 (element substrate) and thesecond substrate 442 and reach the viewing side.

The first electrode layer 447 and the second electrode layer 446 can beformed using a light-transmitting conductive material such as indiumoxide containing tungsten oxide, indium zinc oxide containing tungstenoxide, indium oxide containing titanium oxide, indium tin oxidecontaining titanium oxide, ITO, indium zinc oxide, indium tin oxide towhich silicon oxide is added, or graphene.

The first electrode layer 447 and the second electrode layer 446 can beformed using one or more kinds selected from a metal such as tungsten(W), molybdenum (Mo), zirconium (Zr), hafnium (Hf), vanadium (V),niobium (Nb), tantalum (Ta), chromium (Cr), cobalt (Co), nickel (Ni),titanium (Ti), platinum (Pt), aluminum (Al), copper (Cu), or silver(Ag); an alloy thereof; and a nitride thereof.

A conductive composition containing a conductive polymer can be used toform the first electrode layer 447 and the second electrode layer 446.As the conductive polymer, what is called a π-conjugated conductivepolymer can be used. Examples include polyaniline or a derivativethereof, polypyrrole or a derivative thereof, polythiophene or aderivative thereof, and a copolymer of two or more of aniline, pyrrole,and thiophene or a derivative thereof.

An insulating film serving as a base film may be provided between thefirst substrate 441 and the gate electrode layer 401. The gate electrodelayer 401 can be formed to have a single-layer or layered structureusing a metal such as molybdenum, titanium, chromium, tantalum,tungsten, aluminum, copper, neodymium, or scandium, or an alloy whichcontains any of these metals as its main component. A semiconductor filmwhich is doped with an impurity element such as phosphorus and istypified by a polycrystalline silicon film, or a silicide film of nickelsilicide or the like can also be used as the gate electrode layer 401.By using a light-blocking conductive film as the gate electrode layer401, light from a backlight (light incident from the first substrate441) can be prevented from entering the semiconductor layer 403.

For example, the gate insulating layer 402 can be formed with the use ofa silicon oxide film, a gallium oxide film, an aluminum oxide film, asilicon nitride film, a silicon oxynitride film, an aluminum oxynitridefilm, or a silicon nitride oxide film. Alternatively, a high-k materialsuch as hafnium oxide, yttrium oxide, lanthanum oxide, hafnium silicate,hafnium aluminate, hafnium silicate to which nitrogen is added, orhafnium aluminate to which nitrogen is added may be used as a materialfor the gate insulating layer 402. The use of such a high-k materialenables a reduction in gate leakage current.

Note that the silicon oxide film can be formed by a CVD method in whichan organosilane gas is used. As an organosilane gas, asilicon-containing compound such as tetraethoxysilane (TEOS) (chemicalformula: Si(OC₂H₅)₄), tetramethylsilane (TMS) (chemical formula:Si(CH₃)₄), tetramethylcyclotetrasiloxane, octamethylcyclotetrasiloxane(OMCTS), hexamethyldisilazane (HMDS), triethoxysilane (chemical formula:SiH(OC₂H₅)₃), or trisdimethylaminosilane (chemical formula:SiH(N(CH₃)₂)₃) can be used. Note that the gate insulating layer 402 mayhave a single layer structure or a layered structure.

A material of the semiconductor layer 403 is not limited to a particularmaterial and may be determined in accordance with characteristics neededfor the transistor 420, as appropriate. Examples of a material that canbe used for the semiconductor layer 403 will be described.

The semiconductor layer 403 can be formed using the following material:an amorphous semiconductor formed by a chemical vapor deposition methodusing a semiconductor source gas typified by silane or germane or by aphysical vapor deposition method such as sputtering; a polycrystallinesemiconductor formed by crystallizing the amorphous semiconductor withthe use of light energy or thermal energy; a microcrystallinesemiconductor in which a minute crystalline phase and an amorphous phasecoexist; or the like.

A typical example of an amorphous semiconductor is hydrogenatedamorphous silicon, while a typical example of a crystallinesemiconductor is polysilicon and the like. Polysilicon (polycrystallinesilicon) includes what is called high-temperature polysilicon thatcontains, as its main component, polysilicon formed at a processtemperature of 800° C. or higher, what is called low-temperaturepolysilicon that contains, as its main component, polysilicon formed ata process temperature of 600° C. or lower, and polysilicon formed bycrystallizing amorphous silicon by using an element that promotescrystallization, or the like. Needless to say, as described above, amicrocrystalline semiconductor or a semiconductor which includes acrystal phase in part of a semiconductor layer can also be used.

Alternatively, an oxide semiconductor may be used. In that case, any ofthe following can be used for example: indium oxide, tin oxide, zincoxide, an In—Zn-based oxide, a Sn—Zn-based oxide, an Al—Zn-based oxide,a Zn—Mg-based oxide, a Sn—Mg-based oxide, an In—Mg-based oxide, anIn—Ga-based oxide, an In—Ga—Zn-based oxide (also referred to as IGZO),an In—Al—Zn-based oxide, an In—Sn—Zn-based oxide, a Sn—Ga—Zn-basedoxide, an Al—Ga—Zn-based oxide, a Sn—Al—Zn-based oxide, anIn—Hf—Zn-based oxide, an In—La—Zn-based oxide, an In—Ce—Zn-based oxide,an In—Pr—Zn-based oxide, an In—Nd—Zn-based oxide, an In—Sm—Zn-basedoxide, an In—Eu—Zn-based oxide, an In—Gd—Zn-based oxide, anIn—Tb—Zn-based oxide, an In—Dy—Zn-based oxide, an In—Ho—Zn-based oxide,an In—Er—Zn-based oxide, an In—Tm—Zn-based oxide, an In—Yb—Zn-basedoxide, an In—Lu—Zn-based oxide, an In—Sn—Ga—Zn-based oxide, anIn—Hf—Ga—Zn-based oxide, an In—Al—Ga—Zn-based oxide, anIn—Sn—Al—Zn-based oxide, an In—Sn—Hf—Zn-based oxide, and anIn—Hf—Al—Zn-based oxide. In addition, any of the above oxidesemiconductors may contain an element other than In, Ga, Sn, and Zn, forexample, SiO₂.

Here, for example, an In—Ga—Zn—O-based oxide semiconductor means anoxide semiconductor containing indium (In), gallium (Ga), and zinc (Zn),and there is no limitation on the composition thereof.

For the oxide semiconductor layer, a thin film expressed by a chemicalformula InMO₃(ZnO)_(m) (m>0) can be used. Here, M denotes one or moremetal elements selected from Ga, Al, Mn, and Co. For example, M may beGa, Ga and Al, Ga and Mn, Ga and Co, or the like.

As the oxide semiconductor layer, a CAAC-OS (c-axis aligned crystallineoxide semiconductor) film can be used, for example.

The CAAC-OS film is one of oxide semiconductor films having a pluralityof c-axis aligned crystal parts.

As a material of the wiring layers 405 a and 405 b serving as source anddrain electrode layers, an element selected from Al, Cr, Ta, Ti, Mo, andW; an alloy containing any of the above elements as its component; andthe like can be given. Further, in the case where heat treatment isperformed, the conductive film preferably has heat resistance againstthe heat treatment.

The gate insulating layer 402, the semiconductor layer 403, and thewiring layers 405 a and 405 b serving as source and drain electrodelayers may be successively formed without being exposed to the air. Whenthe gate insulating layer 402, the semiconductor layer 403, and thewiring layers 405 a and 405 b are formed successively without beingexposed to the air, an interface between the layers can be formedwithout being contaminated with atmospheric components or impurityelements included in the air. Thus, variations in characteristics oftransistors can be reduced.

Note that the semiconductor layer 403 is partly etched so as to have agroove (a depression portion).

As the insulating film 407 and the insulating film 409 which cover thetransistor 420, an inorganic insulating film or an organic insulatingfilm formed by a dry method or a wet method can be used. For example, itis possible to use a silicon nitride film, a silicon oxide film, asilicon oxynitride film, an aluminum oxide film, or a tantalum oxidefilm, which is formed by a CVD method, a sputtering method, or the like.It is also possible to use a low-dielectric constant material (a low-kmaterial), a siloxane-based resin, PSG (phosphosilicate glass), BPSG(borophosphosilicate glass), or the like. A gallium oxide film may alsobe used as the insulating film 407. Alternatively, an organic materialsuch as a polyimide, an acrylic resin, a benzocyclobutene-based resin, apolyamide, or an epoxy resin can be used.

Note that the siloxane-based resin is a resin including a Si—O—Si bondformed using a siloxane-based material as a starting material. Thesiloxane-based resin may include as a substituent an organic group(e.g., an alkyl group or an aryl group) or fluorine. In addition, theorganic group may include fluorine. A siloxane-based resin is applied bya coating method and baked; thus, the insulating film 407 can be formed.

Alternatively, the insulating film 407 and the insulating film 409 maybe formed by stacking a plurality of insulating films formed using anyof these materials. For example, the insulating film 407 and theinsulating film 409 may each have such a structure that an organic resinfilm is stacked over an inorganic insulating film.

In the above manner, by using the liquid crystal composition includingthe dioxolane derivative represented by General Formula (G1), (G2),(G3), or (G4) and a nematic liquid crystal, a liquid crystal element orliquid crystal display device that can be driven at a low drivingvoltage can be provided. Thus, a reduction in power consumption of theliquid crystal display device can be achieved.

Further, the liquid crystal composition including the dioxolanederivative represented by General Formula (G1), (G2), (G3), or (G4) anda nematic liquid crystal and exhibiting a blue phase is capable of quickresponse. Thus, by using the liquid crystal composition, ahigh-performance liquid crystal display device can be provided.

The structures, methods, and the like described in this embodiment canbe combined as appropriate with any of the structures, methods, and thelike described in the other embodiments.

(Embodiment 6)

A liquid crystal display device having a display function can bemanufactured by using transistors in a pixel portion and further in adriver circuit. Further, part or the whole of the driver circuit can beformed over the same substrate as the pixel portion, whereby asystem-on-panel can be obtained.

The liquid crystal display device includes a liquid crystal element(also referred to as a liquid crystal display element) as a displayelement.

A liquid crystal display module includes a panel in which a displayelement is sealed, and a component in which an IC or the like includinga controller is mounted to the panel. One embodiment of the presentinvention also relates to an element substrate, which corresponds to onemode before the display element is completed in a manufacturing processof the liquid crystal display device, and the element substrate isprovided with a means for supplying current to the display element ineach of a plurality of pixels. Specifically, the element substrate maybe in a state in which only a pixel electrode of the display element isprovided, a state after formation of a conductive film to be a pixelelectrode and before etching of the conductive film to form the pixelelectrode, or any other states.

Note that a liquid crystal display device in this specification means animage display device or a light source (including a lighting device).Furthermore, a liquid crystal display device also refers to all thefollowing display modules in some cases: a display module in which aconnector, for example, a flexible printed circuit (FPC) or a tapecarrier package (TCP) is attached to a liquid crystal display device, adisplay module in which a printed wiring board is provided at an end ofa TCP, and a display module in which an integrated circuit (IC) isdirectly mounted on a liquid crystal display device by a chip on glass(COG) method.

The display module may include a touch sensor panel provided over theliquid crystal display device. Note that a panel for a touch sensor isnot necessarily provided separately; the display module may include anin-cell or on-cell touch sensor panel in which, for example, anelectrode for a touch sensor is provided on a counter substrate of theliquid crystal display device. Furthermore, the display module mayinclude a backlight, an optical film (a polarizing plate, a retardationplate, or a luminance increasing film), and the like.

The appearance and a cross section of a liquid crystal display panel (adisplay module) which corresponds to a liquid crystal display device ofone embodiment of the present invention will be described with referenceto FIGS. 4A1, 4A2 and 4B. FIGS. 4A1 and 4A2 are top views of a panel inwhich transistors 4010 and 4011 and a liquid crystal element 4013 whichare formed over a first substrate 4001 are sealed between the firstsubstrate 4001 and a second substrate 4006 with a sealant 4005. FIG. 4Bis a cross-sectional view taken along M-N of FIGS. 4A1 and 4A2.

The sealant 4005 is provided so as to surround a pixel portion 4002 anda scan line driver circuit 4004 which are provided over the firstsubstrate 4001. The second substrate 4006 is provided over the pixelportion 4002 and the scan line driver circuit 4004. Thus, the pixelportion 4002 and the scan line driver circuit 4004 are sealed togetherwith a liquid crystal composition 4008, by the first substrate 4001, thesealant 4005, and the second substrate 4006.

In FIG. 4A1, a signal line driver circuit 4003 that is formed using asingle crystal semiconductor film or a polycrystalline semiconductorfilm over a substrate separately prepared is mounted in a region that isdifferent from the region surrounded by the sealant 4005 over the firstsubstrate 4001. FIG. 4A2 illustrates an example in which part of asignal line driver circuit is formed with the use of a transistor whichis provided over the first substrate 4001. A signal line driver circuit4003 b is formed over the first substrate 4001 and a signal line drivercircuit 4003 a which is formed using a single crystal semiconductor filmor a polycrystalline semiconductor film is mounted over a substrateseparately prepared.

Note that there is no particular limitation on the connection method ofa driver circuit which is separately formed, and a COG method, a wirebonding method, a TAB method, or the like can be used. FIG. 4A1illustrates an example of mounting the signal line driver circuit 4003by a COG method, and FIG. 4A2 illustrates an example of mounting thesignal line driver circuit 4003 by a TAB method.

The pixel portion 4002 and the scan line driver circuit 4004 providedover the first substrate 4001 include a plurality of transistors. FIG.4B illustrates the transistor 4010 included in the pixel portion 4002and the transistor 4011 included in the scan line driver circuit 4004,as an example. An insulating layer 4020 and an interlayer film 4021 areprovided over the transistors 4010 and 4011.

Any of the transistors shown in Embodiment 5 can be used as thetransistors 4010 and 4011.

Further, a conductive layer may be provided over the interlayer film4021 or the insulating layer 4020 so as to overlap with a channelformation region of a semiconductor layer of the transistor 4011 for thedriver circuit. The conductive layer may have the same potential as or apotential different from that of a gate electrode layer of thetransistor 4011 and can function as a second gate electrode layer.Further, the potential of the conductive layer may be GND, or theconductive layer may be in a floating state.

A pixel electrode layer 4030 and a common electrode layer 4031 areprovided over the interlayer film 4021, and the pixel electrode layer4030 is electrically connected to the transistor 4010. The liquidcrystal element 4013 includes the pixel electrode layer 4030, the commonelectrode layer 4031, and the liquid crystal composition 4008. Note thata polarizing plate 4032 a and a polarizing plate 4032 b are provided onthe outer sides of the first substrate 4001 and the second substrate4006, respectively.

A liquid crystal composition including the dioxolane derivativerepresented by General Formula (G1), (G2), (G3) or (G4) shown inEmbodiments 1 to 3 and a nematic liquid crystal is used as the liquidcrystal composition 4008. The structures of the pixel electrode layerand the common electrode layer described in any of the above embodimentscan be used for the pixel electrode layer 4030 and the common electrodelayer 4031.

In this embodiment, the liquid crystal composition including thedioxolane derivative represented by General Formula (G1), (G2), (G3), or(G4) and a nematic liquid crystal and exhibiting a blue phase is used asthe liquid crystal composition 4008. The liquid crystal composition 4008is formed by performing the polymer stabilization treatment on theliquid crystal composition in the blue phase state. Therefore, in thisembodiment, at least one of the pixel electrode layer 4030 and thecommon electrode layer 4031 has an opening portion or a comb-shape asillustrated in FIG. 1A described in Embodiment 4 or FIGS. 3A to 3Ddescribed in Embodiment 5.

With a lateral electric field applied between the pixel electrode layer4030 and the common electrode layer 4031, liquid crystal of the liquidcrystal composition 4008 is controlled. Hence, a wide viewing angle isobtained.

As the first substrate 4001 and the second substrate 4006, glass,plastic, or the like having a light-transmitting property can be used.As plastic, a fiber-reinforced plastics (FRP) plate, a poly(vinylfluoride) (PVF) film, a polyester film, or an acrylic resin film can beused. In addition, a sheet with a structure in which an aluminum foil isinterposed between PVF films or polyester films can be used.

A columnar spacer denoted by reference numeral 4035 is obtained byselective etching of an insulating film and is provided in order tocontrol the thickness (a cell gap) of the liquid crystal composition4008. Alternatively, a spherical spacer may also be used. In the liquidcrystal display device including the liquid crystal composition 4008,the cell gap which is the thickness of the liquid crystal composition ispreferably greater than or equal to 1 μm and less than or equal to 20μm. In this specification, the thickness of a cell gap refers to thelength (film thickness) of a thickest part of a liquid crystalcomposition.

Although FIGS. 4A1, 4A2, and 4B illustrate examples of transmissiveliquid crystal display devices, one embodiment of the present inventioncan also be applied to a transflective liquid crystal display device anda reflective liquid crystal display device.

In the example of the liquid crystal display device illustrated in FIGS.4A1, 4A2, and 4B, the polarizing plates are provided on the outer sidesof the first substrate 4001 and the second substrate 4006; however, thepolarizing plate may be provided on the inner side of the substrates.The position of the polarizing plate may be determined as appropriatedepending on the material of the polarizing plate and conditions of themanufacturing process. Furthermore, a light-blocking layer serving as ablack matrix may be provided.

A color filter layer or a light-blocking layer may be formed as part ofthe interlayer film 4021. In FIGS. 4A1, 4A2, and 4B, a light-blockinglayer 4034 is provided on the second substrate 4006 side so as to coverthe transistors 4010 and 4011. With the provision of the light-blockinglayer 4034, the contrast can be increased and the transistors can bemore highly stabilized.

In FIG. 4B, the transistors 4010 and 4011 may be, but is notnecessarily, covered with the insulating layer 4020 which functions as aprotective film of the transistors. Note that the protective film isprovided to prevent entry of impurities such as organic substance,metal, or moisture existing in the air and is preferably a dense film.For example, the protective film may be formed by a sputtering method tohave a single-layer structure or a layered structure including any of asilicon oxide film, a silicon nitride film, a silicon oxynitride film, asilicon nitride oxide film, an aluminum oxide film, an aluminum nitridefilm, an aluminum oxynitride film, and an aluminum nitride oxide film.

Furthermore, a light-transmitting insulating layer may be further formedas a planarizing insulating film.

For the pixel electrode layer 4030 and the common electrode layer 4031,a light-transmitting conductive material can be used.

A variety of signals and potentials are supplied to the signal linedriver circuit 4003 which is separately formed, the scan line drivercircuit 4004, or the pixel portion 4002 from an FPC 4018.

Since the transistor is easily broken by static electricity or the like,a protection circuit for protecting the driver circuits is preferablyprovided over the same substrate as a gate line or a source line. Theprotection circuit is preferably formed using a nonlinear element.

In FIGS. 4A1, 4A2, and 4B, a connection terminal electrode 4015 isformed using the same conductive film as that of the pixel electrodelayer 4030, and a terminal electrode 4016 is formed using the sameconductive film as that of source and drain electrode layers of thetransistors 4010 and 4011.

The connection terminal electrode 4015 is electrically connected to aterminal included in the FPC 4018 via an anisotropic conductive film4019.

Although FIGS. 4A1, 4A2, and 4B illustrate an example in which thesignal line driver circuit 4003 is formed separately and mounted on thefirst substrate 4001, one embodiment of the present invention is notlimited to this structure. The scan line driver circuit may beseparately formed and then mounted, or only part of the signal linedriver circuit or part of the scan line driver circuit may be separatelyformed and then mounted.

In the above manner, by using the liquid crystal composition includingthe dioxolane derivative represented by General Formula (G1), (G2),(G3), or (G4) and a nematic liquid crystal, the liquid crystal elementor the liquid crystal display device can be driven at a low drivingvoltage. Thus, a reduction in power consumption of the liquid crystaldisplay device can be achieved.

Further, the liquid crystal composition including the dioxolanederivative represented by General Formula (G1), (G2), (G3), or (G4) anda nematic liquid crystal and exhibiting a blue phase is capable of quickresponse. Thus, by using the liquid crystal composition for a liquidcrystal display device, a high-performance liquid crystal display devicecan be provided.

The structures, methods, and the like described in this embodiment canbe combined as appropriate with any of the structures, methods, and thelike described in the other embodiments.

(Embodiment 7)

A liquid crystal display device disclosed in this specification can beused for a variety of electronic appliances (including game machines).Examples of such electronic appliances include a television set (alsoreferred to as a television or a television receiver), a monitor of acomputer or the like, a camera such as a digital camera or a digitalvideo camera, a digital photo frame, a mobile phone handset (alsoreferred to as a mobile phone or a mobile phone device), a portable gamemachine, a personal digital assistant, an audio reproducing device, alarge game machine such as a pinball machine, and the like.

FIG. 5A illustrates a laptop personal computer, which includes a mainbody 3001, a housing 3002, a display portion 3003, a keyboard 3004, andthe like. The liquid crystal display device described in any of theabove embodiments is used for the display portion 3003, whereby a laptoppersonal computer with low power consumption can be provided.

FIG. 5B illustrates a personal digital assistant (PDA), which includes amain body 3021 provided with a display portion 3023, an externalinterface 3025, operation buttons 3024, and the like. A stylus 3022 isincluded as an accessory for operation. The liquid crystal displaydevice described in any of the above embodiments is used for the displayportion 3023, whereby a personal digital assistant with low powerconsumption can be provided.

FIG. 5C illustrates an e-book reader, which includes two housings, ahousing 2701 and a housing 2703. The housing 2701 and the housing 2703are combined with a hinge 2711 so that the e-book reader can be openedand closed with the hinge 2711 as an axis. With such a structure, thee-book reader can operate like a paper book.

A display portion 2705 and a display portion 2707 are incorporated inthe housing 2701 and the housing 2703, respectively. The display portion2705 and the display portion 2707 may display one image or differentimages. In the structure where different images are displayed in theabove display portions, for example, the right display portion (thedisplay portion 2705 in FIG. 5C) can display text and the left displayportion (the display portion 2707 in FIG. 5C) can display images. Theliquid crystal display device described in any of the above embodimentsis used for the display portions 2705 and 2707, whereby an e-book readerwith low power consumption can be provided. In the case of using atransflective or reflective liquid crystal display device for thedisplay portion 2705, the e-book reader may be used in a comparativelybright environment; accordingly, a solar cell may be provided so thatpower generation by the solar cell and charge by a battery can beperformed. When a lithium ion battery is used as the battery, there areadvantages of downsizing and the like.

FIG. 5C illustrates an example in which the housing 2701 is providedwith an operation portion and the like. For example, the housing 2701 isprovided with a power switch 2721, operation keys 2723, a speaker 2725,and the like. With the operation keys 2723, pages can be turned. Notethat a keyboard, a pointing device, or the like may also be provided onthe surface of the housing, on which the display portion is provided. Anexternal connection terminal (an earphone terminal, a USB terminal, orthe like), a recording medium insertion portion, and the like may beprovided on the back surface or the side surface of the housing.Further, the e-book reader may have a function of an electronicdictionary.

The e-book reader may transmit and receive data wirelessly. Throughwireless communication, desired book data or the like can be purchasedand downloaded from an electronic book server.

FIG. 5D illustrates a mobile phone, which includes two housings, ahousing 2800 and a housing 2801. The housing 2801 includes a displaypanel 2802, a speaker 2803, a microphone 2804, a pointing device 2806, acamera lens 2807, an external connection terminal 2808, and the like.The housing 2800 includes a solar cell 2810 for charging the mobilephone, an external memory slot 2811, and the like. Further, an antennais incorporated in the housing 2801. The liquid crystal display devicedescribed in any of the above embodiments is used for the display panel2802, whereby a mobile phone with low power consumption can be provided.

The display panel 2802 is provided with a touch panel. A plurality ofoperation keys 2805 which is displayed as images is illustrated bydashed lines in FIG. 5D. Note that a boosting circuit by which a voltageoutput from the solar cell 2810 is increased to be sufficiently high foreach circuit is also included.

In the display panel 2802, the display direction can be appropriatelychanged depending on a usage pattern. The mobile phone is provided withthe camera lens 2807 on the same surface as the display panel 2802, andthus it can be used as a video phone. The speaker 2803 and themicrophone 2804 can be used for videophone calls, recording and playingsound, and the like as well as voice calls. Further, the housings 2800and 2801 which are developed as illustrated in FIG. 5D can overlap witheach other by sliding; thus, the size of the mobile phone can bedecreased, which makes the mobile phone suitable for being carried.

The external connection terminal 2808 can be connected to an AC adapterand various types of cables such as a USB cable, and charging and datacommunication with a personal computer are possible. A large amount ofdata can be stored and can be moved by inserting a storage medium intothe external memory slot 2811.

In addition to the above functions, an infrared communication function,a television reception function, or the like may be provided.

FIG. 5E illustrates a digital video camera, which includes a main body3051, a display portion 3057, an eyepiece 3053, an operation switch3054, a display portion 3055, a battery 3056, and the like. The liquidcrystal display device described in any of the above embodiments is usedfor the display portion 3057 and the display portion 3055, whereby adigital video camera with low power consumption can be provided.

FIG. 5F illustrates a television device, which includes a housing 9601,a display portion 9603, and the like. The display portion 9603 candisplay images. Here, the housing 9601 is supported by a stand 9605. Theliquid crystal display device described in any of the above embodimentsis used for the display portion 9603, whereby a television device withlow power consumption can be provided.

The television device can be operated with an operation switch of thehousing 9601 or a separate remote controller. The remote controller maybe provided with a display portion for displaying data output from theremote controller.

Note that the television device is provided with a receiver, a modem,and the like. With the use of the receiver, general televisionbroadcasting can be received. Furthermore, when the television device isconnected to a communication network by wired or wireless connection viathe modem, one-way (from a transmitter to a receiver) or two-way(between a transmitter and a receiver, between receivers, or the like)data communication can be performed.

The structures, methods, and the like described in this embodiment canbe combined as appropriate with any of the structures, methods, and thelike described in the other embodiments.

EXAMPLE 1

This example shows an example for synthesizing(4R,5R)-2,2-dimethyl-α,α,α′,α′-tetra[4-(trans-4-n-pentylcyclohexyl)phenyl]-1,3-dioxolane-4,5-dimethanol (abbreviation: R-DOL-PC5), which is the dioxolanederivative represented by Structural Formula (100) in Embodiment 1.

Into a 100-mL three-necked-flask, 0.33 g (13 mmol) of magnesium was put,and the air in the flask was replaced with nitrogen. Into this flask,5.0 mL of tetrahydrofuran and several drops of dibromoethane were added,and the mixture was stirred at room temperature. To this mixture, asolution containing 3.9 g (14 mmol) of1-bromo-4-[trans-4-(n-pentyl)cyclohexyl]benzene in 10 mL oftetrahydrofuran was dropped from a dropping funnel with stirring themixture. Then, the mixture was further stirred at 80° C. for 1 hourunder a nitrogen stream. After a predetermined period, a solutioncontaining 0.61 g (2.8 mmol) of (−)-2,3-O-isopropylidene-L-tartaric aciddimethyl ester in 5.0 mL of tetrahydrofuran was dropped to the mixturefrom a dropping funnel with stirring the mixture. Then, the mixture wasfurther stirred at 80° C. for 11.5 hours under a nitrogen stream. Aftera predetermined period, methanol, water, and a dilute hydrochloric acidwere added in this order to the mixture, and an aqueous layer wassubjected to extraction with toluene. The extracted solution and theorganic layer were combined, washed with water, a saturated aqueoussolution of sodium hydrogen carbonate, and saturated saline, and driedwith magnesium sulfate.

This mixture was separated by gravity filtration, and the obtainedfiltrate was concentrated to give a yellow oily substance. The oilysubstance was purified by silica gel column chromatography (developingsolvent: toluene). The resulting fraction was concentrated and dried ina vacuum to give a yellow oily substance. This oily substance waspurified by high performance liquid column chromatography (HPLC)(developing solvent: chloroform). The resulting fraction wasconcentrated and dried in a vacuum to give 1.5 g of the targetlight-yellow solid of R-DOL-PC5 in a yield of 51%. The scheme of theabove reactions is shown in (E1-1).

This compound was identified as the target R-DOL-PC5 by nuclear magneticresonance (NMR).

¹H NMR data of the obtained substance, R-DOL-PC5, are as follows. ¹H NMR(TCE, 300 MHz): δ (ppm)=0.89-1.46 (m, 82H), 1.80-1.98 (m, 16H), 2.32 (s,2H), 2.37-2.50 (m, 4H), 4.58 (s, 2H), 7.03-7.40 (m, 16H).

FIGS. 6A and 6B and FIG. 7 show the ¹H NMR charts. Note that FIG. 6B isan enlarged chart showing a range of from 0 ppm to 5 ppm of FIG. 6A, andFIG. 7 is an enlarged chart showing a range of from 5 ppm to 10 ppm ofFIG. 6A. The measurement results show that R-DOL-PC5, which was thetarget substance, was obtained.

HTP of a liquid crystal composition that is a mixture of R-DOL-PC5synthesized in this example and a nematic liquid crystal was measured.The measurement was performed at room temperature by the Grandjean-Canowedge method. Note that the mixture ratio of the nematic liquid crystalto R-DOL-PC5 in the liquid crystal composition was 99.9 wt %:0.1 wt %(=nematic liquid crystal: R-DOL-PC5). As the nematic liquid crystal, amixed liquid crystal containing a mixed liquid crystal E-8 (produced byLCC Corporation, Ltd.),4-(trans-4-n-propylcyclohexyl)-3′,4′-difluoro-1,1′-biphenyl(abbreviation: CPP-3FF) (produced by Daily Polymer Corporation), and4-n-pentylbenzoic acid 4-cyano-3-fluorophenyl ester (abbreviation:PEP-5CNF) (produced by Daily Polymer Corporation) was used. The mixtureratio was 40 wt %:30 wt %:30 wt % (=E-8: CPP-3FF: PEP-5CNF).

The measurement results show that the HTP of the liquid crystalcomposition including R-DOL-PC5 was 29 μm⁻¹, and by adding an extremelysmall amount of R-DOL-PC5 into the liquid crystal composition, theliquid crystal composition can have high HTP. Thus, R-DOL-PC5 is achiral material having strong twisting power, which means that theproportion of a chiral material in a liquid crystal composition can bereduced.

Thus, R-DOL-PC5 synthesized in this example has proved favorable as achiral material of a liquid crystal composition. Furthermore, the liquidcrystal composition in which one embodiment of the present invention isused has strong twisting power, so that a liquid crystal display devicewith high contrast can be achieved with the use of the liquid crystalcomposition.

EXAMPLE 2

This example shows an example for synthesizing(4R,5R)-2,2-dimethyl-α,α,α′,α′-tetra[4′-(n-hexyl-1-oxy)-1,1′-biphenyl-4-yl]-1,3-dioxolane-4,5-dimethanol(abbreviation: R-DOL-PPO6), which is the dioxolane derivativerepresented by Structural Formula (101) in Embodiment 1.

Into a 100-mL three-necked-flask, 0.44 g (18 mmol) of magnesium was put,and the air in the flask was replaced with nitrogen. Into this flask,5.0 mL of tetrahydrofuran and several drops of dibromoethane were added,and the mixture was stirred at room temperature. To this mixture, asolution containing 6.3 g (19 mmol) of4-bromo-4′-(n-hexyl-1-oxy)-1,1′-biphenyl in 10 mL of tetrahydrofuran wasdropped from a dropping funnel with stirring the mixture. Then, themixture was further stirred at 80° C. for 1 hour under a nitrogenstream. After a predetermined period, a solution containing 0.83 g (3.8mmol) of (−)-2,3-O-isopropylidene-L-tartaric acid dimethyl ester in 3.9mL of tetrahydrofuran was dropped to the mixture from a dropping funnelwith stirring the mixture. Then, the mixture was further stirred at 80°C. for 7.5 hours under a nitrogen stream. After a predetermined period,methanol, water, and a dilute hydrochloric acid were added in this orderto the mixture, and an aqueous layer was subjected to extraction withethyl acetate. The extracted solution and the organic layer werecombined, washed with water, a saturated aqueous solution of sodiumhydrogen carbonate, and saturated saline, and dried with magnesiumsulfate.

This mixture was separated by gravity filtration, and the obtainedfiltrate was concentrated to give a yellow oily substance. The oilysubstance was purified by silica gel column chromatography (developingsolvent:a mixed solvent of hexane:ethyl acetate=10:1, then a mixedsolvent of hexane: ethyl acetate=5:1, and then ethyl acetate). Theresulting fraction was concentrated to give a yellow oily substance.This oily substance was purified by HPLC (developing solvent:chloroform). The resulting fraction was concentrated and dried in avacuum to give 0.57 g of the target yellow oily substance of R-DOL-PPO6in a yield of 13%. The scheme of the above reaction is shown in (E2-1).

This compound was identified as the target R-DOL-PPO6 by NMR.

¹H NMR data of the obtained substance, R-DOL-PPO6, are as follows. ¹HNMR (TCE, 300 MHz): δ (ppm)=0.88-0.94 (m, 12H), 1.16 (s, 6H), 1.24-1.49(m, 18H), 1.74-1.86 (m, 8H), 3.95-4.03 (m, 8H), 4.71 (s, 2H), 6.90-6.99(m, 8H), 7.39-7.64 (m, 24H).

FIGS. 8A and 8B and FIG. 9 show the ¹H NMR charts. Note that FIG. 8B isan enlarged chart showing a range of from 0 ppm to 5 ppm of FIG. 8A, andFIG. 9 is an enlarged chart showing a range of from 5 ppm to 10 ppm ofFIG. 8A. The measurement results show that R-DOL-PPO6, which was thetarget substance, was obtained.

HTP of a liquid crystal composition that is a mixture of R-DOL-PPO6synthesized in this example and a nematic liquid crystal was measured.The measurement was performed at room temperature by the Grandjean-Canowedge method. Note that the mixture ratio of the nematic liquid crystalto R-DOL-PPO6 in the liquid crystal composition was 99.9 wt %:0.1 wt %(=nematic liquid crystal: R-DOL-PPO6). As the nematic liquid crystal, amixed liquid crystal containing a mixed liquid crystal E-8 (produced byLCC Corporation, Ltd.), CPP-3FF (produced by Daily Polymer Corporation),and PEP-5CNF (produced by Daily Polymer Corporation) was used. Themixture ratio was 40 wt %:30 wt %:30 wt % (=E-8: CPP-3FF: PEP-5CNF).

The measurement results show that the HTP of the liquid crystalcomposition including R-DOL-PPO6 was 43 μm⁻¹, and by adding an extremelysmall amount of R-DOL-PPO6 into the liquid crystal composition, theliquid crystal composition can have high HTP. Thus, R-DOL-PPO6 is achiral material having strong twisting power, which means that theproportion of a chiral material in a liquid crystal composition can bereduced.

Thus, R-DOL-PPO6 synthesized in this example has proved favorable as achiral material of a liquid crystal composition. Furthermore, the liquidcrystal composition in which one embodiment of the present invention isused has strong twisting power, so that a liquid crystal display devicewith high contrast can be achieved with the use of the liquid crystalcomposition.

EXAMPLE 3

This example shows an example for synthesizing(4R,5R)-2,2-dimethyl-α,α,α′,α′-tetra[4′-(n-pentyl)-1,1′-biphenyl-4-yl]-1,3-dioxolane-4,5-dimethanol(abbreviation: R-DOL-PP5), which is the dioxolane derivative representedby Structural Formula (102) in Embodiment 1.

Into a 100-mL three-necked-flask, 0.34 g (14 mmol) of magnesium was put,and the air in the flask was replaced with nitrogen. Into this flask,5.0 mL of tetrahydrofuran and several drops of dibromoethane were added,and the mixture was stirred at room temperature. To this mixture, asolution containing 4.4 g (15 mmol) of4-bromo-4′-(n-pentyl)-1,1′-biphenyl in 7.0 mL of tetrahydrofuran wasdropped from a dropping funnel with stirring the mixture. Then, themixture was further stirred at 80° C. for 1 hour under a nitrogenstream. After a predetermined period, a solution containing 0.63 g (2.9mmol) of (−)-2,3-O-isopropylidene-L-tartaric acid dimethyl ester in 2.0mL of tetrahydrofuran was dropped to the mixture from a dropping funnelwith stirring the mixture. Then, the mixture was further stirred at 80°C. for 1 hour under a nitrogen stream. After a predetermined period,methanol, water, and a hydrochloric acid were added in this order to themixture, and an aqueous layer was subjected to extraction with toluene.The extracted solution and the organic layer were combined, washed withwater, a saturated aqueous solution of sodium bicarbonate, and saturatedsaline, and dried with magnesium sulfate.

This mixture was separated by gravity filtration, and the obtainedfiltrate was concentrated to give a yellow oily substance. The oilysubstance was purified by silica gel column chromatography (developingsolvent:a mixed solvent of hexane:ethyl acetate=5:1). The resultingfraction was concentrated to give a yellow oily substance. This oilysubstance was purified by HPLC (developing solvent: chloroform). Theresulting fraction was concentrated and dried in a vacuum to give 2.1 gof the target light-yellow solid of R-DOL-PP5 in a yield of 68%. Thescheme of the above reaction is shown in (E3-1).

This compound was identified as the target R-DOL-PP5 by NMR.

¹H NMR data of the obtained substance, R-DOL-PP5, are as follows. ¹H NMR(TCE, 300 MHz): δ (ppm)=0.90 (s, 12H), 1.16 (s, 6H), 1.24-1.36 (m, 16H),1.60-1.71 (m, 8H), 2.61 (s, 8H), 3.69 (s, 2H), 4.76 (s, 2H), 7.16-7.23(m, 8H), 7.44-7.61 (m, 24H).

FIGS. 10A and 10B and FIG. 11 show the ¹H NMR charts. Note that FIG. 10Bis an enlarged chart showing a range of from 0 ppm to 5 ppm of FIG. 10A,and FIG. 11 is an enlarged chart showing a range of from 5 ppm to 10 ppmof FIG. 10A. The measurement results show that R-DOL-PP5, which was thetarget substance, was obtained.

HTP of a liquid crystal composition that is a mixture of R-DOL-PP5synthesized in this example and a nematic liquid crystal was measured.The measurement was performed at room temperature by the Grandjean-Canowedge method. Note that the mixture ratio of the nematic liquid crystalto R-DOL-PP5 in the liquid crystal composition was 99.9 wt %:0.1 wt %(=nematic liquid crystal: R-DOL-PP5). As the nematic liquid crystal, amixed liquid crystal containing a mixed liquid crystal E-8 (produced byLCC Corporation, Ltd.), CPP-3FF (produced by Daily Polymer Corporation),and PEP-5CNF (produced by Daily Polymer Corporation) was used. Themixture ratio was 40 wt %:30 wt %:30 wt % (=E-8: CPP-3FF: PEP-5CNF).

The measurement results show that the HTP of the liquid crystalcomposition including R-DOL-PP5 was 50 μm⁻¹, and by adding an extremelysmall amount of R-DOL-PP5 into the liquid crystal composition, theliquid crystal composition can have high HTP. Thus, R-DOL-PP5 is achiral material having strong twisting power, which means that theproportion of a chiral material in a liquid crystal composition can bereduced.

Thus, R-DOL-PP5 synthesized in this example has proved favorable as achiral material of a liquid crystal composition. Furthermore, the liquidcrystal composition in which one embodiment of the present invention isused has strong twisting power, so that a liquid crystal display devicewith high contrast can be achieved with the use of the liquid crystalcomposition.

EXAMPLE 4

In this example, three kinds of liquid crystal compositions that areeach one embodiment of the present invention and three kinds of TN modeliquid crystal elements including the liquid crystal compositions wereprepared, and characteristics of the liquid crystal compositions and theliquid crystal elements were evaluated.

In the three kinds of liquid crystal compositions made in this example,a mixed liquid crystal ZLI-4792 (produced by Merck) was used in commonas a nematic liquid crystal. As chiral materials for the respectiveliquid crystal compositions, R-DOL-PC5, R-DOL-PPO6, and R-DOL-PP5described in Examples 1 to 3, respectively, were used. In the liquidcrystal compositions, the proportions of the chiral materials R-DOL-PC5,R-DOL-PPO6, and R-DOL-PP5 with respect to the nematic liquid crystalZLI-4792 were 0.03 wt %, 0.04 wt %, and 0.03 wt %, respectively.

The helical pitches of the three kinds of liquid crystal compositionsprepared in this example were 49.7 μm, 55.2 μm, and 103.7 μm, which weremeasured at room temperature by the Grandjean-Cano wedge method.

Then, the alignment in the transmissive TN cells before and aftervoltage application was observed. The TN cells were the cells forvertical electric field application with a cell thickness of 4 μm. Apixel electrode layer was formed using indium tin oxide containingsilicon oxide (ITSO) by a sputtering method over each of two glasssubstrates. The thickness of the pixel electrode layer was 110 nm. Then,SE-6414 (produced by Nissan Chemical Industries, Ltd.) was applied as ahorizontal alignment film over each of the glass substrates with a spincoater, and was baked at 230° C. Next, rubbing treatment was performedwith a rubbing apparatus, and spacers with a diameter of 4 μm weredispersed over one of the substrates. A heat-curable sealing materialwas applied over the substrate over which the spacers were dispersed,and the two substrates were bonded to each other such that the rubbingdirections of the substrates intersect each other. The bonded substrateswere subjected to heat treatment at 160° C. for 4 hours while beingpressed with a pressure of 0.3 kgf/cm².

The substrates formed in the above manner were divided, and the threekinds of liquid crystal compositions were injected by an injectingmethod using capillary action, so that three kinds of liquid crystalelements were fabricated. These three kinds of liquid crystal elementswere observed by crossed nicols observation with a polarizing microscope(MX-61L produced by Olympus Corporation), which showed that line defectsdue to a reverse twist were not generated at all and favorable alignmentwas obtained in all the liquid crystal elements.

Next, voltage-transmittance characteristics of these three kinds ofliquid crystal elements were measured with a RETS+VT measurement system(produced by Otsuka Electronics Co., Ltd.). The voltage was applied at0.2 V intervals in the range of from 0 V to 10 V. After the measurement,crossed nicols observation with the polarizing microscope was performedagain, which showed that, in all the three kinds of liquid crystalelements, line defects due to the reverse twist were not generated atall and favorable alignment was obtained also after the voltageapplication.

The above-described results indicate that the liquid crystalcompositions of embodiments of the present invention can be used for TNmode elements by including the dioxolane derivative represented byGeneral Formula (G1) as a chiral material.

EXAMPLE 5

In this example, R-DOL-PC5 whose synthesis method is shown in Example 1and a nematic liquid crystal were mixed to prepare a liquid crystalcomposition. Note that the mixture ratio of the nematic liquid crystalto R-DOL-PC5 in the liquid crystal composition was 86.0 wt %:14.0 wt %(=nematic liquid crystal: R-DOL-PC5). As the nematic liquid crystal, amixed liquid crystal containing a mixed liquid crystal E-8 (produced byLCC Corporation, Ltd.), CPP-3FF (produced by Daily Polymer Corporation),and PEP-5CNF (produced by Daily Polymer Corporation) was used. Themixture ratio was 40 wt %:30 wt %:30 wt % (=E-8: CPP-3FF: PEP-5CNF).

In this example, the liquid crystal composition in the liquid crystalelement was made to be an isotropic phase at first. Then, the liquidcrystal composition was observed with a polarizing microscope while thetemperature was decreased by 1.0° C. per minute with a temperaturecontroller, and the temperature at which the liquid crystal compositionis transformed to a blue phase was measured. The liquid crystalcomposition of this example exhibited a blue phase at 42.3° C.

EXAMPLE 6

In this example, R-DOL-PP5 whose synthesis method is shown in Example 3and a nematic liquid crystal were mixed to prepare a liquid crystalcomposition. Note that the mixture ratio of the nematic liquid crystalto R-DOL-PP5 in the liquid crystal composition was 89.2 wt %:10.8 wt %(=nematic liquid crystal: R-DOL-PP5). As the nematic liquid crystal, amixed liquid crystal containing a mixed liquid crystal E-8 (produced byLCC Corporation, Ltd.), CPP-3FF (produced by Daily Polymer Corporation),and PEP-5CNF (produced by Daily Polymer Corporation) was used. Themixture ratio was 40 wt %:30 wt %:30 wt % (=E-8: CPP-3FF: PEP-5CNF).

In this example, the liquid crystal composition in the liquid crystalelement was made to be an isotropic phase at first. Then, the liquidcrystal composition was observed with a polarizing microscope while thetemperature was decreased by 1.0° C. per minute with a temperaturecontroller, and the temperature range where the liquid crystalcomposition exists in a blue phase was measured. In the liquid crystalcomposition of this example, the phase transition temperature between anisotropic phase and a blue phase was 46.2° C., and a phase transitiontemperature between a blue phase and a cholesteric phase was 41.4° C.

The above results show that the liquid crystal composition of oneembodiment of the present invention can exhibit a blue phase byincluding the dioxolane derivative represented by General Formula (G1)as a chiral material.

EXAMPLE 7

This example shows an example for synthesizing(4R,5R)-2,2-dimethyl-α,α,α′,α′-tetra(naphthalen-1-yl)-1,3-dioxolane-4,5-dimethanol(abbreviation: R-DOL-αNp), which is the dioxolane derivative representedby Structural Formula (200) in Embodiment 2.

Into a 300-mL three-necked-flask, 1.6 g (64 mmol) of magnesium was put,and the air in the flask was replaced with nitrogen. Into this flask, 15mL of tetrahydrofuran and several drops of dibromoethane were added, andthe mixture was stirred at room temperature. To this mixture, a solutioncontaining 11 mL (75 mmol) of 1-bromonaphthalene in 30 mL oftetrahydrofuran was dropped from a dropping funnel with stirring themixture. Then, the mixture was further stirred at 80° C. for 1 hourunder a nitrogen stream. After a predetermined period, a solutioncontaining 2.7 mL (15 mmol) of (−)-2,3-O-isopropylidene-L-tartaric aciddimethyl ester in 10 mL of tetrahydrofuran was dropped to the mixturefrom a dropping funnel with stirring the mixture. Then, the mixture wasfurther stirred at 80° C. for 1 hour under a nitrogen stream. After apredetermined period, methanol, water, and a dilute hydrochloric acidwere added in this order to the mixture, and an aqueous layer wassubjected to extraction with ethyl acetate. The extracted solution andthe organic layer were combined, washed with water, a saturated aqueoussolution of sodium hydrogen carbonate, and saturated saline, and driedwith magnesium sulfate.

This mixture was separated by gravity filtration, and the obtainedfiltrate was concentrated to give a red oily substance. The oilysubstance was purified by HPLC (developing solvent: chloroform). Theresulting fraction was concentrated to give a light-yellow solid. Theobtained solid was washed with methanol and suction filtered to give 1.2g of the target white solid of R-DOL-αNp in a yield of 17%. The schemeof the above reaction is shown in (E4-1).

This compound was identified as the target R-DOL-αNp by NMR.

¹H NMR data of the obtained substance, R-DOL-αNp, are as follows. ¹H NMR(TCE, 300 MHz): δ (ppm)=0.52 (s, 2H), 1.35 (s, 6H), 3.41 (s, 2H),6.89-8.08 (m, 28H).

FIGS. 12A and 12B and FIG. 13 show the ¹H NMR charts. Note that FIG. 12Bis an enlarged chart showing a range of from 0 ppm to 5 ppm of FIG. 12A,and FIG. 13 is an enlarged chart showing a range of from 5 ppm to 10 ppmof FIG. 12A. The measurement results show that R-DOL-αNp, which was thetarget substance, was obtained.

HTP of a liquid crystal composition that is a mixture of R-DOL-αNpsynthesized in this example and a nematic liquid crystal was measured.The measurement was performed at room temperature by the Grandjean-Canowedge method. Note that the mixture ratio of the nematic liquid crystalto R-DOL-αNp in the liquid crystal composition was 99.9 wt %:0.1 wt %(=nematic liquid crystal: R-DOL-αNp). As the nematic liquid crystal, amixed liquid crystal containing a mixed liquid crystal E-8 (produced byLCC Corporation, Ltd.), CPP-3FF (produced by Daily Polymer Corporation),and PEP-5CNF (produced by Daily Polymer Corporation) was used. Themixture ratio was 40 wt %:30 wt %:30 wt % (=E-8: CPP-3FF: PEP-5CNF).

The measurement results show that the HTP of the liquid crystalcomposition including R-DOL-αNp was 88 μm⁻¹, and by adding an extremelysmall amount of R-DOL-αNp into the liquid crystal composition, theliquid crystal composition can have high HTP. Thus, R-DOL-αNp is achiral material having strong twisting power, which means that theproportion of a chiral material in a liquid crystal composition devicecan be reduced.

Thus, R-DOL-αNp synthesized in this example has proved favorable as achiral material of a liquid crystal composition. Furthermore, the liquidcrystal composition in which one embodiment of the present invention isused has strong twisting power, so that a liquid crystal display devicewith high contrast can be achieved with the use of the liquid crystalcomposition.

EXAMPLE 8

This example shows an example for synthesizing(4R,5R)-2,2-dimethyl-α,α,α′,α′-tetra(pyren-1-yl)-1,3-dioxolane-4,5-dimethanol(abbreviation: R-DOL-Prna), which is the dioxolane derivativerepresented by Structural Formula (201) in Embodiment 2.

Into a 100-mL three-necked-flask, 0.36 g (15 mmol) of magnesium was put,and the air in the flask was replaced with nitrogen. Into this flask,5.0 mL of tetrahydrofuran and several drops of dibromoethane were added,and the mixture was stirred at room temperature. To this mixture, asolution containing 4.8 g (16 mmol) of 1-bromopyrene in 10 mL oftetrahydrofuran was dropped from a dropping funnel with stirring themixture. Then, the mixture was further stirred at 80° C. for 1 hourunder a nitrogen stream. After a predetermined period, a solutioncontaining 0.68 g (3.1 mmol) of (−)-2,3-O-isopropylidene-L-tartaric aciddimethyl ester in 5.0 mL of tetrahydrofuran was dropped to the mixturefrom a dropping funnel with stirring the mixture. Then, the mixture wasfurther stirred at 80° C. under a nitrogen stream. After a predeterminedperiod, methanol, water, and a dilute hydrochloric acid were added inthis order to the mixture, and an aqueous layer was subjected toextraction with ethyl acetate. The extracted solution and the organiclayer were combined, washed with water, a saturated aqueous solution ofsodium hydrogen carbonate, and saturated saline, and dried withmagnesium sulfate.

This mixture was separated by gravity filtration, and the obtainedfiltrate was concentrated to give a brown solid. The solid was purifiedby silica gel column chromatography (developing solvent:a mixed solventof hexane:ethyl acetate=5:1). The resulting fraction was concentratedand dried in a vacuum to give a brown solid. This solid was purified byHPLC (developing solvent: chloroform). The obtained fraction wasconcentrated and dried in a vacuum to give a brown oily substance. Tothe oily substance was added hexane, followed by irradiation withultrasonic waves. The resulting solid was recrystallized with toluene.The obtained solid was suction filtered and dried in a vacuum, and thenpurified by flash column chromatography (developing solvent:chloroform). The resulting fraction was concentrated to give a yellowoily substance. To this oily substance was added a mixed solvent oftoluene/hexane, and the precipitated solid was suction filtered anddried in a vacuum to give 5.0 mg of the target white solid of R-DOL-Prnain a yield of 0.17%. The scheme of the above reaction is shown in(E5-1).

This compound was identified as the target R-DOL-Prna by NMR.

¹H NMR data of the obtained substance, R-DOL-Prna, are as follows. ¹HNMR (TCE, 300 MHz): δ (ppm)=1.15 (s, 2H), 1.36 (s, 6H), 6.50 (s, 2H),7.24-8.79 (m, 36H).

FIGS. 14A and 14B and FIG. 15 show the ¹H NMR charts. Note that FIG. 14Bis an enlarged chart showing a range of from 0 ppm to 5 ppm of FIG. 14A,and FIG. 15 is an enlarged chart showing a range of from 5 ppm to 10 ppmof FIG. 14A. The measurement results show that R-DOL-Prna, which was thetarget substance, was obtained.

HTP of a liquid crystal composition that is a mixture of R-DOL-Prnasynthesized in this example and a nematic liquid crystal was measured.The measurement was performed at room temperature by the Grandjean-Canowedge method. Note that the mixture ratio of the nematic liquid crystalto R-DOL-Prna in the liquid crystal composition was 99.9 wt %:0.1 wt %(=nematic liquid crystal R-DOL-Prna). As the nematic liquid crystal, amixed liquid crystal containing a mixed liquid crystal E-8 (produced byLCC Corporation, Ltd.), CPP-3FF (produced by Daily Polymer Corporation),and PEP-5CNF (produced by Daily Polymer Corporation) was used. Themixture ratio was 40 wt %:30 wt %:30 wt % (=E-8: CPP-3FF PEP-5CNF).

The measurement results show that the HTP of the liquid crystalcomposition including R-DOL-Prna was 110 μm⁻¹, and by adding anextremely small amount of R-DOL-Prna into the liquid crystalcomposition, the liquid crystal composition can have high HTP. Thus,R-DOL-Prna is a chiral material having strong twisting power, whichmeans the proportion of a chiral material in a liquid crystalcomposition can be reduced.

Thus, R-DOL-Prna synthesized in this example has proved favorable as achiral material of a liquid crystal composition. Furthermore, the liquidcrystal composition in which one embodiment of the present invention isused has strong twisting power, so that a liquid crystal display devicewith high contrast can be achieved with the use of the liquid crystalcomposition.

EXAMPLE 9

In this example, two kinds of liquid crystal compositions that are eachone embodiment of the present invention and two kinds of TN mode liquidcrystal elements including the liquid crystal compositions wereprepared, and characteristics of the liquid crystal compositions and theliquid crystal elements were evaluated.

In the two kinds of liquid crystal compositions prepared in thisexample, a mixed liquid crystal ZLI-4792 (produced by Merck) was used incommon as a nematic liquid crystal. As chiral materials for therespective liquid crystal compositions, R-DOL-αNpand R-DOL-Prnadescribed in Examples 7 and 8, respectively, were used. In both of theliquid crystal compositions, the proportion of the chiral materialR-DOL-αNp and R-DOL-Prna with respect to the nematic liquid crystalZLI-4792 was 0.01 wt %.

The helical pitches of the two kinds of liquid crystal compositionsprepared in this example were 72.8 μm and 55.3 μm, which were measuredat room temperature by the Grandjean-Cano wedge method.

Then, the alignment in the transmissive TN cells before and aftervoltage application was observed. The TN cells were prepared in the sameway as that described in Example 4.

The resulting two kinds of liquid crystal elements were observed bycrossed nicols observation with a polarizing microscope (MX-61L producedby Olympus Corporation), which showed that line defects due to a reversetwist were not generated at all and favorable alignment was obtained inall the liquid crystal elements.

Next, voltage-transmittance characteristics of these two kinds of liquidcrystal elements were measured with a RETS+VT measurement system(produced by Otsuka Electronics Co., Ltd.). The voltage was applied at0.2 V intervals in the range of from 0 V to 10 V. After the measurement,crossed nicols observation with the polarizing microscope was performedagain, which showed that, in both kinds of liquid crystal elements, linedefects due to the reverse twist were not generated at all and favorablealignment was obtained also after the voltage application.

The above-described results indicate that the liquid crystalcompositions of embodiments of the present invention can be used for TNmode elements by including the dioxolane derivative represented byGeneral Formula (G2) as a chiral material.

EXAMPLE 10

In this example, (R-DOL-Prna whose synthesis method is shown in Example8 and a nematic liquid crystal were mixed to prepare a liquid crystalcomposition. Note that the mixture ratio of the nematic liquid crystalto R-DOL-Prna in the liquid crystal composition was 94.9 wt %:5.1 wt %(=nematic liquid crystal: R-DOL-Prna). As the nematic liquid crystal, amixed liquid crystal containing a mixed liquid crystal E-8 (produced byLCC Corporation, Ltd.), CPP-3FF (produced by Daily Polymer Corporation),and PEP-SCNF (produced by Daily Polymer Corporation) was used. Themixture ratio was 40 wt %:30 wt %:30 wt % (=E-8: CPP-3FF: PEP-5CNF).

In this example, the liquid crystal composition in the liquid crystalelement was made to be an isotropic phase at first. Then, the liquidcrystal composition was observed with a polarizing microscope while thetemperature was decreased by 1.0° C. per minute with a temperaturecontroller, and the temperature at which the liquid crystal compositionis transformed to a blue phase was measured. The liquid crystalcomposition of this example exhibited a blue phase at 50.3° C.

The above results show that the liquid crystal composition of oneembodiment of the present invention can exhibit a blue phase byincluding the dioxolane derivative represented by General Formula (G2)as a chiral material.

EXAMPLE 11

This example shows an example for synthesizing(4R,5R)-2,2-dimethyl-1,3-dioxolane-4,5-dimethanol bis{4-[4-(n-hexyl-1-oxy)phenyl]benzoate} (abbreviation: R-DOL-1EPPO6),which is the dioxolane derivative represented by Structural Formula(300) in Embodiment 3.

Into a 50-mL recovery flask, 0.34 g (2.1 mmol) of(−)-2,3-O-isopropylidene-D-threitol, 1.3 g (4.2 mmol) of4-[4-(n-hexyl-1-oxy)phenyl]benzoic acid, 0.22 g (1.8 mmol) ofN,N-dimethyl-4-aminopyridine (DMAP), and 2.1 mL of dichloromethane wereput, and the mixture was stirred. To this mixture, 0.88 g (4.6 mmol) of1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC) wasadded, and this mixture was stirred overnight at room temperature underatmospheric pressure. After a predetermined period, water was added, andthe aqueous layer of the obtained mixture was subjected to extractionwith dichloromethane. The extracted solution and the organic layer werecombined, washed with water, a saturated aqueous solution of sodiumhydrogen carbonate, and saturated saline, and dried with magnesiumsulfate.

This mixture was separated by gravity filtration, and the obtainedfiltrate was concentrated to give a light-brown solid. This solid waspurified by silica gel column chromatography (developing solvent:chloroform). The resulting fraction was concentrated to give a whitesolid. This solid was purified by HPLC (developing solvent: chloroform).The resulting fraction was concentrated to give a white solid. To thissolid, hexane and methanol were added, and the mixture was subjected toirradiation with ultrasonic waves. The solid was suction-filtered togive 0.87 g of the target white solid of R-DOL-1EPPO6 in a yield of 58%.The scheme of the above reaction is shown in (E6-1).

This compound was identified as the target R-DOL-1EPPO6 by NMR.

¹H NMR data of the obtained substance. R-DOL-1EPPO6, are as follows. ¹HNMR (CDCl₃, 300 MHz): δ (ppm)=0.92 (s, 6H), 1.32-1.38 (m, 12H), 1.49 (s,6H), 1.76-1.86 (m, 4H), 4.00 (t, 4H), 4.36 (s, 2H), 4.49-4.62 (m, 4H),6.97 (d, 2H), 7.54 (d, 2H), 7.61 (d, 2H), 8.08 (d, 2H).

FIGS. 16A and 16B and FIG. 17 show the ¹H NMR charts. Note that FIG. 16Bis an enlarged chart showing a range of from 0 ppm to 5 ppm of FIG. 16A,and FIG. 17 is an enlarged chart showing a range of from 5 ppm to 10 ppmof FIG. 16A. The measurement results show that R-DOL-1EPPO6, which wasthe target substance, was obtained.

HTP of a liquid crystal composition that is a mixture of R-DOL-1EPPO6synthesized in this example and a nematic liquid crystal was measured.The measurement was performed at room temperature by the Grandjean-Canowedge method. Note that the mixture ratio of the nematic liquid crystalto R-DOL-1EPPO6 in the liquid crystal composition was 99.9 wt %:0.1 wt %(=nematic liquid crystal: R-DOL-1EPPO6). As the nematic liquid crystal,a mixed liquid crystal containing a mixed liquid crystal E-8 (producedby LCC Corporation, Ltd.), CPP-3FF (produced by Daily PolymerCorporation), and PEP-5CNF (produced by Daily Polymer Corporation) wasused. The mixture ratio was 40 wt %:30 wt %:30 wt % (=E-8: CPP-3FF:PEP-5CNF).

The measurement results show that the HTP of the liquid crystalcomposition including R-DOL-1EPPO6 was 84 and by adding an extremelysmall amount of R-DOL-1EPPO6 into the liquid crystal composition, theliquid crystal composition can have high HTP. Thus, R-DOL-1EPPO6 is achiral material having strong twisting power, which means that theproportion of a chiral material in a liquid crystal composition can bereduced.

Thus, R-DOL-1EPPO6 synthesized in this example has proved favorable as achiral material of a liquid crystal composition. Furthermore, the liquidcrystal composition in which one embodiment of the present invention isused has strong twisting power, so that a liquid crystal display devicewith high contrast can be achieved with the use of the liquid crystalcomposition.

EXAMPLE 12

In this example, a liquid crystal composition of one embodiment of thepresent invention and a TN mode liquid crystal element including theliquid crystal composition were prepared, and characteristics of theliquid crystal composition and the liquid crystal element wereevaluated.

In the liquid crystal composition prepared in this example, a mixedliquid crystal ZLI-4792 (produced by Merck) was used as a nematic liquidcrystal. As a chiral material, R-DOL-1EPPO6 described in Example 11 wasused. In the liquid crystal composition, the proportion of the chiralmaterial R-DOL-1EPPO6 with respect to the nematic liquid crystalZLI-4792 was 0.04 wt %.

The helical pitch of the liquid crystal composition prepared in thisexample was 182.6 μm, which was measured at room temperature by theGrandjean-Cano wedge method.

Then, the alignment in the transmissive TN cells before and aftervoltage application was observed. The TN cells were prepared in the sameway as that described in Example 4.

The resulting liquid crystal element was observed by crossed nicolsobservation with a polarizing microscope (MX-61L produced by OlympusCorporation), which showed that line defects due to a reverse twist werenot generated at all and favorable alignment was obtained.

Next, voltage-transmittance characteristics of this liquid crystalelement were measured with a RETS+VT measurement system (produced byOtsuka Electronics Co., Ltd.). The voltage was applied at 0.2 Vintervals in the range of from 0 V to 10 V. After the measurement,crossed nicols observation with the polarizing microscope was performedagain, which showed that line defects due to the reverse twist were notgenerated at all and favorable alignment was obtained also after thevoltage application.

The above-described results indicate that the liquid crystal compositionof one embodiment of the present invention can be used for a TN modeelement by including the dioxolane derivative represented by GeneralFormula (G4) as a chiral material.

EXAMPLE 13

In this example, R-DOL-1EPPO6 whose synthesis method is shown in Example11 and a nematic liquid crystal were mixed to prepare a liquid crystalcomposition. Note that the mixture ratio of the nematic liquid crystalto R-DOL-1EPPO6 in the liquid crystal composition was 93.3 wt %:6.7 wt %(=nematic liquid crystal: R-DOL-1EPPO6). As the nematic liquid crystal,a mixed liquid crystal containing a mixed liquid crystal E-8 (producedby LCC Corporation, Ltd.), CPP-3FF (produced by Daily PolymerCorporation), and PEP-5CNF (produced by Daily Polymer Corporation) wasused. The mixture ratio was 40 wt %:30 wt %:30 wt % (=E-8: CPP-3FF:PEP-5CNF).

In this example, the liquid crystal composition in the liquid crystalelement was made to be an isotropic phase at first. Then, the liquidcrystal composition was observed with a polarizing microscope while thetemperature was decreased by 1.0° C. per minute with a temperaturecontroller, and the temperature at which the liquid crystal compositionis transformed to a blue phase was measured. It was confirmed that theliquid crystal composition of this example exhibited a blue phase at62.4° C. [0[

]310]

The above results show that the liquid crystal composition of oneembodiment of the present invention can exhibit a blue phase byincluding the dioxolane derivative represented by General Formula (G4)as a chiral material.

This application is based on Japanese Patent Application serial no.2013-159187 filed with Japan Patent Office on Jul. 31, 2013, JapanesePatent Application serial no. 2013-159194 filed with Japan Patent Officeon Jul. 31, 2013, and Japanese Patent Application serial no. 2013-159197filed with Japan Patent Office on Jul. 31, 2013, the entire contents ofwhich are hereby incorporated by reference.

What is claimed is:
 1. A compound represented by formula (G2):

wherein: Ar¹ and Ar² independently represent hydrogen, a substituted orunsubstituted aryl group having 6 to 12 carbon atoms, a substituted orunsubstituted cycloalkyl group having 3 to 12 carbon atoms, or asubstituted or unsubstituted cycloalkenyl group having 4 to 12 carbonatoms; Ar²³ and Ar²⁴ independently represent a substituted orunsubstituted pyrenyl group; a¹ and a² independently represent asubstituted or unsubstituted alkylene group having 1 to 4 carbon atomsor a single bond; and R¹ and R² independently represent hydrogen, asubstituted or unsubstituted alkyl group having 1 to 6 carbon atoms, asubstituted or unsubstituted alkoxy group having 1 to 6 carbon atoms, ora substituted or unsubstituted aryl group having 6 to 12 carbon atoms.2. The compound according to claim 1, wherein: Ar¹ and Ar² eachrepresent hydrogen; and a¹ and a² each represent a single bond.
 3. Thecompound according to claim 1, wherein the compound is optically active.4. The compound according to claim 1, wherein the compound isrepresented by formula (201):


5. A composition comprising: the compound according to claim 1; and aliquid crystal.
 6. A liquid crystal display device comprising thecomposition according to claim
 5. 7. A compound represented by formula(G4):

wherein: Ar⁴¹ represents a substituted or unsubstituted arylene grouphaving 6 to 12 carbon atoms; n represents 2; R¹ and R² independentlyrepresent hydrogen, a substituted or unsubstituted alkyl group having 1to 6 carbon atoms, a substituted or unsubstituted alkoxy group having 1to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6to 12 carbon atoms; R³ represents hydrogen, a substituted orunsubstituted alkyl group having 1 to 6 carbon atoms, or a substitutedor unsubstituted alkoxy group having 1 to 6 carbon atoms.
 8. Thecompound according to claim 7, wherein R³ represents a substituted orunsubstituted alkoxy group having 1 to 6 carbon atoms.
 9. The compoundaccording to claim 7, wherein the compound is optically active.
 10. Thecompound according to claim 7, wherein the compound is represented byformula (300):


11. A composition comprising: the compound according to claim 7; and aliquid crystal.
 12. A liquid crystal display device comprising thecomposition according to claim 11.